SK279811B6 - Transparent, fire-resistant, glazing panels, and method of its production - Google Patents

Abstract

Transparent, fire-resistant, glazing panels comprise at least one layer of intumescent material bonded to at least one structural ply of the panel. Such a panel comprises a structural ply (1, 2) which is bonded to an intumescent layer (3), which has been formed by compacting grains of an intumescent hydrated metal salt, and which has a total water content in the range 20 to 26 percent inclusive. Such a panel may be manufactured by a method in which grains of an intumescent hydrated metal salt having a total water content of between 22 percent and 26 percent by weight are distributed as a layer on a surface of a ply to be incorporated into the panel, and in which, while the layer of grains is sandwiched between a pair of moulding plates, that layer is subjected to heat and pressure conditions to degas and compact it and cause it to become bonded to that surface of the ply of the panel.

Description

Technical field

The invention relates to a transparent (transparent) fireproof glazing panel comprising at least one layer of swellable material associated with at least one structural layer of the panel. The invention further relates to a method of manufacturing this transparent fireproof glazing panel.

BACKGROUND OF THE INVENTION

A method of bonding layers of swellable material to sheets of glazing material to form fireproof panels is known in the art. For example, this layer of swellable material may be clamped between two glass sheets. Very important applications of such panels are transparent screens that allow illumination of the screened area and closures of the vents for rooms or other closures where there is a risk of fire.

Typically, the performance of such panels is tested by incorporating them into the furnace wall, the internal temperature of which then increases according to a predetermined mode. Details of the performance of these tests are given in the International Standard ISO 834-1975. The fire resistance testing procedure described in this standard is also given in ISO 9051-1990, which deals specifically with the fire resistance of glazed assemblies. It is appropriate to list some parts of this standard.

Glass is a non-combustible material and therefore does not contribute to the spread of fire.

Glass exposed to heat may burst by thermal shock or soften and then will not be held by the frame Thus, only some types of glazed assemblies can be considered fireproof. The ability of glazing assemblies to resist fire depends on the type of glazed article, the glazing method, the frame type, the panel size, the fastening method and the type of structure surrounding the glazed area.

Some transparent and translucent glazing assemblies may meet stability and integrity (RE) requirements and, in some cases, insulation performance (REI) where R stands for resistance, E for sealing and I for insulation.

It is not enough to consider only the possibility of direct fire propagation through the openings caused by the refraction of glass when the fire protection is examined; it is also necessary to take into account the heat-permeable glazing assembly, which in this case can remain intact, and such heat can cause the ignition of combustible materials.

Glazed assemblies with fire resistance according to the RE class under the fire conditions defined in ISO 834 ensure the stability and integrity of the assembly over a given period of time. The temperature of the unexposed side is disregarded.

Glazed assemblies with fire resistance according to the REI class under the fire conditions defined in ISO 834 ensure, over a given period of time, the stability, integrity and insulating ability of the assembly.

There are different degrees of fire resistance of a given panel, and among these generally considered parameters are grades that correspond to the quality of the panels, which create effective barriers to flame and smoke (which is a RE class) for periods of 15, 30, 45, 60, 90 and 120 minutes. . Other grades correspond to panels that constitute effective barriers to flame and smoke passage and also have some insulating properties (which is the REI class), again for periods of 15, 30, 45, 60, 90 and 120 minutes.

In brief, the insulating properties that a panel must have to meet the REI standard are such that no surface point that is outside the furnace shall be subject to a temperature increase of more than 180 ° C above its initial or ambient temperature and an increase in mean temperature. of this surface shall not exceed 140 ° C. Such panels belonging to the REI class may also form obstacles to the transmission of infrared radiation from the fire bearing.

In these cases, it is extremely important that the layer of swellable material of such a panel has good flame retardant or flame retardant properties, and also retains acceptable optical properties as it swells when exposed to the flame.

For many years, hydrated metal salts, such as metal silicates, especially alkali metal silicates, have been used to produce such panels. In a conventional embodiment, the layers incorporated in the finished panels had a water content of from 29% to 35% by weight. As used herein, the water content is the proportion by weight of water relative to the content of the swellable material used to form the layer or the proportion by weight relative to the swellable material incorporated as a layer in the finished panel prior to the outbreak and subsequent remodeling. During the fire, the hydration water is expelled by the heat generated by the fire, and the layer of swellable material is transformed into an opaque foam which acts as an obstacle to radiated heat and conduction heat and may also serve to connect structural layers of the panel, such as glass layers. they may be disturbed by the thermal shock caused by the fire. The effectiveness of this panel as an obstacle to flame and smoke penetration is thus prolonged in this way

The effectiveness of hitherto known types of panels as fire screens depends on several factors. The efficiency of laminated assemblies consisting of a single layer of a given swellable material clamped between two glass sheets of a given thickness increases with the thickness of the swellable material. For a given prior art panel with a given weight per unit area, i.e., for the same total thickness of glass and swellable material, the efficiency of such a known panel can be increased by forming as a five-layer laminate comprising two layers of swellable material clamped between three glass panes A laminate of three 4 mm glass panes enclosing two layers of swellable material of 1 mm thickness proved to be much more effective than a laminate of two 6 mm thick glass panes, enclosing one layer of swellable material of 2 mm thickness. Thus, the same efficiency can be achieved by using a thinner panel having multiple layers. It is clear from the above that it is desirable to focus on producing high-performance fireproof panels that have a low weight per unit area, but the manufacture of panels with four or more layers can be very costly.

Another problem associated with the use of hydrated metal salt layers as layers of swellable material is the aging of the material with time. This aging is manifested as a violation of the optical properties of the panel, for example, a reduction in the transparency of the hydrated swellable material, which reduces the transparency of the panel. Such a violation of the panel's characteristics is clearly a mistake in its use.

This problem of impairing the optical properties of an aging refractory panel comprising a layer of swellable material has been known in the art for many years. So far, various efforts have been made to solve this problem. The most significant cause of the optical properties was the formation of microbubbles in or on the layer, and the known treatment of this layer by drying a suitable solution of the hydrated metal salt in situ using water that was degassed, taking care not to get too vivid agitated to prevent re-dissolution of air or other gas that might reappear when the dried layer ages. Although this working measure achieves improved panel aging properties, this solution is not entirely satisfactory when the panel is used in conditions where it is exposed to moderate heat, such as direct sunlight. It is also known in the art to add some stabilizing agent to a hydrated metal salt, such as a partially dissociated organic nitrogen compound, for example a quaternary ammonium compound such as tetramethylammonium hydroxide, for better results compared to the prior art.

SUMMARY OF THE INVENTION

SUMMARY OF THE INVENTION The object of the present invention is to provide a transparent refractory glazing panel which has good properties during aging, which is essentially independent of the use of said additives, and which also has good fire-resistance properties.

According to the invention, this object has been solved by providing a transparent (or transparent) fireproof glazing panel comprising at least one layer of swellable material associated with at least one structural layer of the panel, comprising the structural layer associated with a layer of swellable material which has been formed by compacting the grains of the swellable hydrated metal salt and has a total water content of from 20 to 26% by weight.

In a preferred embodiment, the panel comprises two structural layers which are laminated together by said swellable material layer.

Preferably, the swellable material layer has a total water content of at least 22% by weight, even more preferably at least 23% by weight and most preferably at most 25% by weight.

Said granular particles have a maximum size in a preferred embodiment of less than 700 µm, and more preferably are in the range of 150 µm to 500 µm.

Said layer of swellable material has a thickness ranging from 0.1 mm to 5.0 mm

In a preferred embodiment, the swellable material comprises hydrated sodium silicate.

The swellable material layer preferably comprises at least one silicate stabilizing agent, wherein the silicate stabilizing agent comprises at least one nitrogenous organic compound, such as an amino compound, which is at least partially dissociated, for example a quaternary ammonium compound, such as tetramethylammonium hydroxide.

The present invention also relates to a process for the preparation of a transparent refractory glazing panel comprising, in a first stage, the granular particles of swellable hydrated alkali metal silicate having a water content in the range of 22% to 26% by weight, in the form of in a second step, the granular particle layer is sandwiched between a pair of molding plates, and in a third step the layer is subjected to heat and pressure while degassing and compressing to bond with the surface of the structural layer of the panel.

Said structural layer on which the grain is distributed on a surface is preferably a glass plate intended to be incorporated into the panel and forming said molding plate.

The second molding plate is preferably formed or covered by a structural layer intended to be incorporated into the panel, the layer being joined to a layer of swellable material.

In a preferred embodiment of the process according to the invention, at least a portion of the degassing and bonding time is subjected to a layer of swellable material at a temperature of at least 80 ° C, and preferably also to a pressure of less than 30 kPa.

According to the present invention, such a panel has been found to be less susceptible to deterioration of its optical properties over time than prior art panels in which the water content is slightly higher. Indeed, the aging properties of the panel according to the present invention are better than those of a panel whose swellable material has a higher water content in the range of 29 to 34% by weight and which contains a stabilizing agent such as tetramethylammonium hydroxide for the same other parameters. This constitutes an unexpected feature of the present invention, and it is not entirely clear why this favorable result is achieved by using a swellable layer having a lower water content.

It is also surprising according to the present invention that such a panel may have improved fire resistance properties, as it would rather be expected that a lower water content in the swellable layer would reduce the efficiency of the panel, as the foaming ability during fire would be reduced. In fact, it has been found that a three-layer laminate comprising one layer of swellable material sandwiched between two glass sheets according to the present invention has a better fire resistance than a three-layer laminate of similar dimensions, whose swellable layer has a higher water content. Thus, the invention has the additional advantage of allowing the same degree of fire resistance to be achieved by using a thinner and lighter panel without the additional complications and costs associated with increasing the number of laminate layers.

The lower water content of the swellable layer, maximum 26% by weight, will increase its hardness, making it physically more stable and less creeping. According to the invention, it is advantageous to produce a water-containing layer mi

EN 279811 Β6 at least 20% by weight for the manufacture of panels having good transparency.

According to the invention, it is preferred that the layer has a water content of not less than 22% by weight. The presence of such proportions of water in the swellable layer very well promotes foaming properties during exposure to fire and also allows the formation of a hard and compact swellable material layer that maintains good optical properties over time. Optimally, this layer has a total water content of at most 23% by weight.

For best results, it is preferred that this layer has a total water content of no more than 25% by weight, as this promotes maintaining good optical properties independent of panel aging.

This grain layer can be easily compacted by subjecting it to suitable thermal and pressure conditions to form a layer in which the individual grains are not visible to the naked eye, so that the layer has a uniform appearance and is transparent. However, the presence of such grains can be detected, for example, by ultrasound testing or microscope observation, and it is assumed that the grain boundaries, although invisible, remain in the layer. It is contemplated that this layer structure may have some influence on the behavior of the swellable material during fire exposure as well as on the properties of the layer prior to exposure to fire. One of the possible contributing factors for improving the fire resistance of a panel according to the present invention is that although grain boundaries disappear and are not apparent when viewed with the naked eye, these boundaries still exist and act as a system of bubble formation sites for reaction of swellable material during exposure This results in a fine foaming structure having a good and uniform insulating effect over the entire panel surface.

Said grains preferably have a maximum dimension of less than 700 µm, and are preferably greater than 10 µητ, for example having a maximum dimension of between 150 µm and 500 µm. This helps to easily form the grains into a compact layer and can also have a beneficial effect on the behavior of the swellable material during fire. It has been found that panels made with these preferred features of the invention give a fine and uniform foam structure when subjected to the intense heat generated by the fire. It is believed that this is mainly due to the relatively low water content of the swellable material compared to the water content previously used in the manufacture of refractory panels, as well as to the fact that some residual grain remains in the reinforced layer, but the fineness of the residual grain structure may in this layer.

As mentioned above, the effectiveness of the fireproof panel during fire exposure depends at least in part on the thickness of the entire layer or on the thickness of each layer of the swellable material. As already mentioned, it is preferred according to the invention that the layer of swellable material has a thickness in the range of 0.1 to 5.0 mm. Layers with a thickness of 0.1 mm can provide adequate short-term fire protection, although naturally better protection is due to thicker layers. In general, increasing the thickness of such a layer above 5 mm does not give an adequate increase in protection, and it has also been found that it is more difficult to form thicker compact layers having good optical properties.

Said swellable material may be selected from a large number of hydrated metal salts, but the use of alkali metal salts is preferred. Examples of suitable alkali metal salts which may be used in hydrated form include potassium aluminate, potassium lead, potassium tinate, sodium tinate, sodium aluminum sulfate, potassium aluminum aluminum sulfate, sodium borate, potassium borate, sodium orthophosphates and potassium silicate. However, for economic reasons (i.e., cost reasons) and efficiency, it is preferred that the swellable material is hydrated sodium silicate, which may optionally be mixed with hydrated potassium silicate.

In a preferred embodiment of the invention, the panel preferably comprises two structural layers which are laminated with a layer of swellable material. This arrangement represents a very stable and simple panel structure. In the simplest form, such a laminate may consist of two sheets of glazing material that are directly bonded to each side of the swellable material layer. Alternatively, if a higher degree of fire protection is desired, two layers of swellable material may be joined to form a laminated panel with three structural layers of glazing material. It will be appreciated that if more fire protection is desired, two or more such panels may be laminated, for example, by using an intermediate adhesive material such as polyvinyl butyral, which is done in a conventional manner in the art of glazing laminates.

It has already been mentioned above that the aging properties of the panel according to the present invention are better than those of a panel whose swellable material layer has a higher water content in the range of 29% to 34% by weight and contains a stabilizing agent. Thus, it would be natural to believe that there are no reasons for using such a stabilizing agent in a panel whose swellable material layer has a low water content according to the present invention, since such a panel already has very good aging properties. However, the use of such stabilizing agents may mean a further improvement in the aging properties of the panel of the present invention and may have some and totally unexpected advantage that the use of such an agent promotes the fire-retardant properties of the layer during fire exposure, which is particularly beneficial in a panel having multiple swellable layers. material and containing such an additive. Accordingly, it is preferred that such a layer of swellable material comprises at least one silicate-based stabilizing agent.

Preferably, the silicate-based stabilizing agent preferably comprises at least one organic nitrogen compound, for example an amine compound that is at least partially dissociated, such as a quaternary ammonium compound such as tetramethylammonium hydroxide. It is believed that the addition of such a stabilizing agent such as tetramethylammonium hydroxide according to a preferred embodiment of the present invention not only provides a further advantage in terms of panel aging but may also have a beneficial effect on the foam generated during fire exposure and thus contribute to panel fire resistance.

SK 279811Β6

The panel according to the present invention can be manufactured in a very simple manner. According to the invention, a transparent refractory glazing panel is produced comprising at least one layer of swellable material associated with at least one structural layer of the panel, in which the swellable hydrated metal salt grains having a water content of 22% to 26% by weight are distributed over the structural layer to form a composition. which is to be incorporated into the panel and while the grains are clamped between the pair of molding plates, the layer is subjected to thermal and pressure conditions under which degassing and compaction are achieved and bonded to said surface of the panel layer.

This process is very simple in terms of its execution and can be carried out using conventional equipment known in the laminate industry.

In addition to achieving very good aging properties and panel fire resistance, the choice of swellable grains having said water content also provides other benefits. The use of swellable grains having a water content of not more than 26% by weight promotes the retention of the optical properties of the panel irrespective of its aging, which grains are also suitable for handling before and during the manufacture of the panel. The swellable paste having a water content of at least 22% by weight is readily compacted into hard and transparent layers or at least into layers that become transparent when placed between two transparent sheets. This does not necessarily mean that the resulting swellable layer will necessarily have a water content of 22% by weight or more. Some water is likely to be removed during degassing, but the mean water content of the layer will be only slightly lower than the average water content of the grains from which the layer was formed. According to the invention, it has been found that the difference in water content in the grains and in the layer is at most 2%, so that this difference is negligible. For example, a layer made of grains with a mean water content of 25% will have a mean water content of between 23% and 25%. If the lower water content is used for the production of the layer, it is desirable to control the degassing conditions so that only a small amount of water is removed, it is not appropriate that the average water content of the layer is at least 20% %.

During degassing and compaction, the swellable layer is attached to the panel layer with which it is in contact. The layer may be a film of thermoplastic adhesive material, which is then bonded to a structural layer of the panel, such as glass sheets, and for a particularly suitable solution for certain purposes, the process comprises the step of distributing the grain layer on the glass plate surface. is then incorporated into the panel, the plate also forming said molding plate.

Where it is desired that the second molding plate is not bonded to the resultant layer of swellable material, it may be suitably treated, for example with silicone, but it is preferred that the second molding plate is formed by or adjacent to the layer built into the panel and to which the layer of swellable material will be attached. Thus, a layer of swellable material may be sandwiched between two layers of a panel that is laminated together with degassing and compaction. If desired, the panel may be conveyed to an autoclave in the next stage of the process to effect subsequent high temperature bonding.

In this regard, any desired number of successively alternating layers of glazing material and swellable material may be laminated, but the difficulty of producing a laminate having good optical properties increases with the number of layers of swellable material, especially when three layers of composite material are to be compacted simultaneously. or a plurality of such layers, and when the layer assembly is to be subjected to heating during compaction and / or bonding of such layers, as discussed below.

In addition, it is also noted that two or more such panels consisting of alternating layers of glazing material and swellable material can be laminated using a film of adhesive thermoplastic material if greater flame retardancy is desired. Such a process has practical advantages where it is desirable to incorporate a plurality of layers of swellable material into the assembly.

As a practical example, it is necessary to make a fireproof panel having four layers of swellable material, each of approximately

1.5 mm. According to the invention, it has been found that the grain layers of the swellable material to form such reinforced layers must be up to seven times thicker than the compacted layers, so that such a panel can shrink in thickness up to about 36 mm during degassing and bonding. Production is simplified by forming two panels each having two layers of swellable material, which panels are then laminated using an adhesive thermoplastic material such as polyvinyl butyral. The presence of such a film of adhesive thermoplastic material can also have a beneficial effect on the fire-resistance properties of this panel, as it will limit the propagation of fractures due to thermal shock

According to the most preferred embodiments of the invention, the total water content is at least 23% by weight and even more preferably at least 25% by weight. The presence of such proportions of water in the swellable grains results in good foaming properties of the resultant layer during fire exposure and also allows the formation of a hard and compact layer of swellable material that has good optical properties and retains these properties for long periods of time.

Preferably, the grain size is such that at least 90% by weight of the grains have a maximum dimension of less than 700 µm, more preferably the size of the grains ranges from 150 µm to 500 µm. Grains of such sizes are easy to handle and give the resulting compacted layer a structure , which is considered to be beneficial in achieving good fire-resistance properties, as mentioned above. Such grain sizes are also particularly advantageous for forming layers of the most desired thicknesses, for example from 0.1 mm to 5.0 mm.

In a preferred embodiment, at least part of the time during which degassing and bonding takes place, the layer of swellable material is subjected to a temperature of at least 80 ° C. Heating the swellable material to such a temperature aids in degassing and compacting as well as bonding to the panel layer. It should be noted that the swellable material must not be subjected to such high temperatures that, due to the pressure exerted on the swellable material, could cause premature foaming of the swellable material. It should be noted that it is much easier to ensure that a single layer on

The swellable material or each of the two layers of swellable panel material has been subjected to an optimal heating process to ensure that each of the three or more layers is optimally heated, although only because the middle layer or layers are more shielded from of the heat source by other layers of the panel than the outer layers.

According to the invention, it is advantageous that during the degassing and bonding the layer of swellable material is subjected to a pressure of less than 30 kPa. This allows perfect degassing of the swellable material.

The foregoing sections describe the use of additives in a layer of swellable material to improve their aging properties. The use of such an additive may have other unexpected advantages in improving the fire resistance during fire exposure, as mentioned above. Thus, it is preferred that the swellable material comprises at least one silicate-based stabilizing agent and preferably a stabilizing agent comprising at least one organic nitrogen compound, for example an amino compound, which is at least partially dissociated, for example with a quaternary ammonium compound such as tetramethylammonium hydroxide.

BRIEF DESCRIPTION OF THE DRAWINGS

The transparent refractory glazing panel according to the invention is shown in the drawing. 1 schematically illustrates an assembly for degassing and compacting a layer of swellable material by the process of the present invention.

In FIG. 1 shows a panel formed from two glass panes 1, 2 and an intermediate layer 3 of grains of swellable material having a total water content ranging from 22% to 26% by weight. The fraction of these grains is sized so that the grains pass through a 500 µm sieve, but are trapped in 150 µm sieves. These grains are simply dispersed horizontally on the first glass sheet in a layer seven times thicker than the resulting thickness of the compacted layer to be produced. The panel is enclosed in the housing 4. The housing 4 is connected by suction line 5 to the pump 6, which can maintain vacuum in the housing 4 and also between the glass panes 1 and 2. When the pump 6 is started, the upper and lower walls of the housing 4 are attracted to the outer by the surface of the assembly enclosed in the housing 4 and the glass sheets 1, 2 act as molding plates to compact the layer 3 of the swellable material. The housing 4 is at least near its peripheral region 7 strong enough to withstand the gripping against the edges of the stack of layers 1, 2, 3 so that a vacuum is maintained in the cavity 8 by the pump 6 around the edges of the housing 4.

An advantage of using a sleeve 4 that surrounds the stack of layers 1, 2, 3 is that the size of the sleeve 4 with respect to the dimensions of the stack of layers 1, 2, 3 is not critical. The housing 4 can be used for stack assemblies 1, 2, 3 of different sizes. The use of such a sleeve 4 also facilitates the application of the same pressure over the entire surface of the main surfaces of the stack assembly 1, 2, 3 so that the reaction forces resulting from the pressure differences between the environment in which the sleeve 4 is located and the space in the sleeve 4 will not be such that caused bending of sheets 1, 2 of this assembly. Such a bend could lead to the formation of bubbles in the edges of the swellable material layer 3 and could also give rise to an uneven end product.

According to one possible variant of the apparatus described, this assembly is provided with any support means used to absorb the reaction forces resulting from the pressure differences between the inside and the outside of the housing 4. In FIG. 1, such support means are shown as a pair of frames 9 of the same shape, but larger in size than the stack of layers 1, 2, 3, which are held at a certain distance by pillars 10 to retain the housing 4 so as not to contact the edges of the stack 1, 2 3 layers after shrinkage of the swellable material layer 3 to its final thickness as shown in the drawing.

Heating means (not shown) for heating the swellable material layer 3 sandwiched between the glass sheets 1,2 may be provided on the top and bottom surfaces of the housing 4 to facilitate compaction and bonding of the layer assembly 1,2, 3.

The layer assembly 1, 2, 3 shown in FIG. 1 can then be subjected to molding using suction devices, which can be done in a simple manner in which the outer space of the housing 4 is always exposed to air pressure. In one embodiment, the pump 6 is operated to reduce the pressure in the housing, i.e. the pressure applied to the edges of the stack 1, 2, 3 in the peripheral cavity 8, to a value below 30 kPa. The exact optimum value will depend on the water content of the swellable grains used. The setpoint can be reached after a few minutes, and is maintained for an additional 100 minutes. The layer assembly 1, 2, 3 initially has a room temperature, i.e. about 20 ° C, and then the interior of the housing 4 is heated so that after 45 minutes the temperature reaches 90 ° C.

After the desired degassing, the pressure inside the housing is brought back to atmospheric pressure for about 15 minutes. At the end of this time, it can be ensured that the swellable material layer 3 is compacted so that the interfaces between the pitches are not visible to the naked eye and the stack of layers 1, 2, 3 is joined to a transparent laminate panel. If desired, this panel may, of course, optionally be transferred to an autoclave for further high pressure treatment in order to further improve the bonding.

According to the invention, it has been found that the water loss in the swellable material due to suction during compaction of the layer is less than 2% by weight of the layer.

DETAILED DESCRIPTION OF THE INVENTION

The transparent refractory glazing panel according to the invention and the process for producing it will be described in more detail below with reference to specific embodiments, which are illustrative only and are not intended to limit the scope of the invention in any way.

Example 1

As described in the description section, a series of panels were made using 3 mm thick glass sheets with an embedded layer of swellable material of thickness

With a total water content of 23.5% to 24.5% by weight. The layer of swellable material of each such panel was formed from grains having a total water content of 24.5% by weight and sieved so that their size was from 150 µm to 500 µπι The weight ratio of silica to sodium oxide in sodium silicate was

The grains of the swellable material contained no tetramethylammonium hydroxide as an additive promoting fire resistance.

Similarly, a series of comparative test panels of similar dimensions were produced in a conventional manner, in which to form such a panel, the hydrated sodium silicate solution was dried in situ on a 3 mm thick glass sheet to form a 1.8 mm medium thickness, varying the thickness range. in the range of 1.5 mm to 2.1 mm and the total water content was from 29% to 34% by weight. The solution contained 0.25% tetramethylammonium hydroxide as an anti-aging additive. Again, the weight ratio of silica to sodium oxide in sodium silicate was between 3.3: 1 and 3.4: 1. A second 3 mm glass sheet was attached to this layer to form a laminated panel.

The panels were framed in substantially the same frames to create glazing assemblies for testing according to the international standard ISO 834-1975.

Two glazing assemblies, each of one row of panels, were then built side by side into the furnace wall and the furnace was heated according to the desired predetermined mode to test the stability and integrity of both assemblies as barriers to flame and smoke penetration according to the RE class. The benchmark test kit was found to comply with ISO 834 at RE for 30 minutes but not for 45 minutes. The assembly comprising the panel of the present invention complied with ISO 834 at the RE level for more than 60 minutes.

Both types of panels were also tested for aging. In the first test, the panels were maintained at 80 ° C for 15 days. At the end of this time, no microbubbles were visible in the panel of the present invention, while a number of bubbles were visible in the comparative test panel, so that a mist was formed regardless of the presence of a stabilizing agent in the swellable material layer. In the panel according to the present invention, the fog appeared only after 30 days. In the second test, the panels were exposed to ultraviolet radiation for 500 hours. The panel of the present invention did not contain any microbubbles after this time, and the comparative test panel contained more than twice as many bubbles as after the first aging test.

Example 2

According to this example, two further sets of panels according to the invention were made using the same starting materials as in Example 1. In these sets, the panels consisted of three 3 mm glass sheets and two layers of swellable material with a thickness of

1.5 mm. In one panel set according to the invention, the swellable material layers contained a proportion of tetramethylammonium hydroxide, and in the second place there was no such additive. Tetramethylammonium hydroxide was added by addition to a silicate solution from which grains were formed in a proportion of 0.125% by weight. A set of comparative test panels of the same structure was made using a solution of hydrated sodium silicate with tetramethylammonium hydroxide addition as described for the comparative test panels in Example 1. The swellable material layers of such comparative test panels had an average thickness of 1.8 mm.

These panels were again framed into identical frames to create glazing assemblies to perform the test according to the international standard ISO 834-1975.

Such glazing assemblies were then mounted side by side into the furnace wall and the furnace was heated according to the desired predetermined regime for the stability, integrity and insulating ability of both REI class kits. Various assemblies have been found to have the ability to maintain integrity as a barrier to flame and smoke penetration as well as meet insulation performance requirements in the REI class between 30 and 35 minutes

Other products of each glazing assembly were subjected to the aging tests given in Example 1. It was found that in all tests all panels of the invention had better results than the comparative test panels and also that the panels of the invention in which the swellable material contained tetramethylammonium hydroxide, provided better results than panels without it.

Example 3

According to this example, two further sets of panels according to the invention were produced as described in Example 2, except that one of the outer glass panes of the panel had a thickness of 2 mm instead of 3 mm. The panels of each set were laminated with a 2 mm glass sheet inside using 0.76 mm thick polyvinylbutyral embedded films. In one set of these polyvinyl butyral laminated panels each contained four layers of 1.5 mm thickness of hydrated sodium silicate with tetramethylammonium hydroxide, while the other set was not used.

These panels were again framed in substantially identical frames to obtain glazing assemblies to perform the test according to the international standard ISO 834-1975.

The assemblies were then built side by side into the furnace wall and the furnace was heated according to the desired predetermined mode to test the properties of both panel sets, again according to the REI class. It was found that those assemblies whose panels did not contain tetramethylammonium hydroxide were able to maintain integrity as a barrier to flame and smoke penetration and meet the requirements for insulation class REI from 55 to 70 minutes. The assemblies of the invention, whose panels contained tetramethylammonium hydroxide, remained effective as barriers to flame and smoke penetration and met the REI class insulation requirements for 70 to 80 minutes.

Example 4

According to this example, another set of glazing assemblies was made by laminating and framing the three panels of the invention produced by the procedure of Example 2 using 0.76 mm thick polyvinyl butyral layers. The assemblies were then built side by side into the furnace wall and the furnace was heated according to the desired predetermined mode to perform a test for the properties of these assemblies, again according to the REI class. The kits of the present invention have been found to remain effective as barriers to flame and smoke penetration and to meet the REI class insulation requirements for more than 90 minutes, and when tetramethylammonium hydroxide was used as an additive to improve fire resistance, they met the REI class requirements during 110 minutes.

SK 279811Β6

Example 5

Two fire-resistant panels according to the invention were produced, each comprising three 3 mm glass panes and two layers of swellable material with a thickness of 0.6 mm. In one panel, the swellable material contained tetramethylammonium hydroxide as a flame retardant according to Example 2, in in the second panel such an additive was not used.

The framed assemblies containing the two panels were then tested for stability, integrity and insulation performance according to the REI class when exposed to fire. The panel without additive was excited after 34 minutes. The additive panel enjoyed the effects of the test for 35 to 36 minutes.

Example 6

According to this example, two fire-resistant panels were produced, each comprising three glass sheets of 3 mm, 8 mm and 3 mm thickness and two layers of swellable material. In one pan each layer of swellable material was formed according to the invention by the method of Example 1, the layer having a thickness of

2.5 mm In the second panel, the layer of swellable material had a thickness of 1.8 mm, which layer was formed by the classical technique described in relation to the comparative test panel of Example 1.

Framed assemblies containing the two panels were then tested for stability, integrity and insulation performance according to the REI class when exposed to fire. The comparison test panel was disrupted after 40 minutes. The panel according to the invention withstood the effects of this test for 50 minutes.

Claims (22)

A transparent refractory glazing panel comprising at least one layer of swellable material associated with at least one structural layer of the panel, characterized in that the panel comprises a structural layer (1, 2) bonded to the layer of swellable material formed by compressing the swellable particulate particles. % of a hydrated alkali metal silicate having a total water content ranging from 20 to 26% by weight. The transparent refractory glazing panel according to claim 1, characterized in that it comprises two structural layers (1, 2) which are co-laminated by said layer of swellable material. The transparent refractory glazing panel according to claim 1 or 2, characterized in that the swellable material layer (3) has a total water content of at least 22% by weight. The transparent refractory glazing panel according to claim 3, characterized in that the swellable material layer (3) has a total water content of at least 23% by weight. Transparent fire-resistant glazing panel according to one of the preceding claims 1 to 4, characterized in that the swellable material layer (3) has a total water content of not more than 25% by weight. Transparent refractory glazing panel according to any one of claims 1 to 5, characterized in that the granular particles have a maximum size of less than 700 µm and preferably are in the range of 150 µm to 500 µm. Transparent fire-resistant glazing panel according to one of the preceding claims 1 to 6, characterized in that the layer (3) of the swellable material has a thickness in the range from 0.1 mm to 5.0 mm. 8. The transparent refractory glazing panel of any one of claims 1 to 7, wherein the swellable material comprises hydrated sodium silicate. Transparent fire-resistant glazing panel according to one of the preceding claims 1 to 8, characterized in that the layer (3) of the swellable material comprises at least one silicate stabilizing agent. The transparent refractory glazing panel of claim 9, wherein the silicate stabilizing agent comprises at least one nitrogenous organic compound, such as an amino compound, that is at least partially dissociated, for example, a quaternary ammonium compound, such as tetramethylammonium hydroxide. A process for the preparation of a transparent refractory glazing panel according to claims 1 to 9, characterized in that in the first step the granular particles of swellable hydrated alkali metal silicate having a water content in the range of 22% to 26% by weight are distributed as in a second step, the granular particle layer is sandwiched between a pair of molding plates, and in a third stage the layer is subjected to heat and pressure while degassing and compressing to bond with the surface of the structural layer of the panel. 12. The method of claim 11, wherein said structural layer on which the grain is distributed on the surface is a glass plate to be incorporated into the panel and forming said molding plate. 13. The method of claim 12 wherein said second molding plate is formed or covered with a structural layer to be incorporated into the panel, said layer being joined to a layer of swellable material. Method according to any one of claims 11 to 13, characterized in that the granular particles have a moisture content of at least 23% by weight. Method according to any one of claims 11 to 14, characterized in that the granular particles have a moisture content of not more than 25% by weight. Method according to any one of claims 11 to 15, characterized in that the particle size of the particles is such that at least 90% by weight of the particles have a maximum size of less than 700 µm and preferably are in the range of 150 µm to 500 µm. Method according to any one of claims 11 to 16, characterized in that said layer of swellable material is formed to a thickness in the range of 0.1 mm to 5.0 mm. Method according to one of claims 11 to 17, characterized in that said layer The swellable material comprises hydrated sodium silicate. Method according to any one of claims 11 to 18, characterized in that for at least part of the degassing and bonding time the layer of swellable material is subjected to a temperature of at least 80 ° C. Method according to any one of claims 11 to 19, characterized in that during degassing and bonding the layer of swellable material is subjected to a pressure of less than 30 kPa. Method according to any one of claims 11 to 20, characterized in that the swellable material comprises at least one silicate stabilizing agent. The method of claim 21, wherein the silicate stabilizing agent comprises at least one nitrogenous organic compound, such as an amino compound, which is at least partially dissociated, for example, a quaternary ammonium compound such as tetramethylammonium hydroxide.