DK173106B1 - Method of applying binder to mineral wool - Google Patents

Description

DK 173106 B1 Usually, the production of mineral wool products takes place in such a way that a mineral melt is produced in a melting plant, from which the melt is continuously fed to a fibrating plant. In the fiber plant, the melt is to a greater or lesser extent converted into fibers which are removed from the fiber plant by an air or gas stream to a receiver means in the form of a perforated conveyor, on which the fibers are laid as a continuous web, while the air or gas flow continues through the conveyor for a suction device for further transport, eg a treatment plant.

The raw materials may consist of stone or slag, in which case dome ovens are usually used as smelting plants. In that case, fibrillation is not infrequently effected by means of 10 rapidly rotating, internally water-cooled steel cylinders, so-called spinning wheels, which are arranged to receive the melt successively. The melt is thus passed to one of the wheels, from which it is cast to the next wheel etc. This type of construction is called the cascade spinning method or the JM process (JohnsManville). The number of spinning wheels in the cascade is usually between 2 and 4. Less often, more than four spinning wheels occur in the cascade.

To achieve a higher capacity, parallel fibrating devices are sometimes used. Thus, it is common to use two identical or mutually facing mirroring devices located side by side and between which the melt is distributed.

20 In the manufacture of glass wool, more or less conventional glass raw materials are usually used, which are usually melted in a kettle. In this connection, the most commonly used method of vibration is to allow the melt to flow into several hollow centrifuges rotating about vertical axes. A hole is formed in the jacket of the centrifuge, through which the molten glass of the centrifugal force is pressed out in the form of thin rods, so-called primary fibers. The vibration itself is then produced by powerful, axially directed gas or air flows flowing past the casing surfaces of the centrifuges.

Even in the case where rock or slag wool is fibered, air currents occur around the spinning wheels. The airflow has several tasks, including directing the fibers from the fibrating means itself towards the collecting means, the fibers, as mentioned above, being laid on the collecting means as the gas or air flow passes through the collecting means.

In commercial processes for the production of mineral wool products, there is, in principle, this air or gas stream in which the newly formed fibers are more or less well-suspended and which air flow carries the fibers from the fibrating device 35 to the receiving means. If binder is to be added to the mineral wool, as is practically always the case, in most cases the supply is effected by the addition of a finely divided binder to this fiber suspension. Instead of binder or in combination with binder, in principle, other agents can also be added, for example, wetting agent or dusting agent. Often, the feed takes place very close to the fiber element itself. The reason why the binder is applied to the fiber suspension and not to the continuous web formed on the receiving member is that it is difficult to induce the binder to enter a mineral wool structure due to the density of the structure and the fineness of the fibers relative to the size of the binder droplets. .

Two essentially different principles exist for the function or work of the receiving member 10. In accordance with the one principle that was originally used, a finished web is constructed on the conveyor of the receiving body, which is then passed on to cure, cool, divide, cut, etc. In technical terms, this implies that the surface weight, e.g. m2m, already at the first laying on the pervious conveyor of the recipient body is the same, which must later occur in the final product. However, another principle exists which in many cases gives a better result. In accordance with this principle, a relatively thin web is first collected, a so-called primary web, which is then caused by a folding process in one or more steps to form a finished web whose surface weight corresponds to the surface weight of the finished product. The surface weight of the primary web can in many cases be 20 far less than the finished web, for example a tenth or less.

The air or gas flow which feeds the fibers from the fibrating device to the receiving means is more or less turbulent. However, studies have shown that, especially when the distance is not very large, no complete mixing occurs. This means that the fibers introduced into this air or gas stream in one location tend to substantially settle at a particular location or within a particular area of the receiving conveyor, while fibers introduced into the air or the gas flow at another location in the main case settles within another area. This realization is utilized in the provision of the present invention.

Thus, the binder used in mineral wool products is usually of an organic nature. Phenolic plastics are used almost without exception, which can be modified to a greater or lesser extent. However, the mineral wool can withstand a higher temperature than the organic binder. Accordingly, for certain applications, such as insulation in chimneys or ovens, there are two disadvantages, both of which are flushed, that the binder does not withstand the temperature occurring at these locations.

3 DK 173106 B1

One of these drawbacks is that gases and fumes develop when the binder is burned out, and this results in, among other things, odor problems.

The other disadvantage is that the binder-free mineral wool does not gradually have the same strength required for the particular application. This has led to the attempt to provide a more temperature resistant binder, preferably inorganic. However, it is very difficult to find an inorganic binder that can give the products the same elasticity and resilience as plastic binders. In addition, most people assume that significant amounts of water are supplied. This in turn causes drying problems. Most mineral wool fabrication devices are intended for use with a plastic binder that can be fixed in a very short time in so-called army ovens. If a water-based inorganic binder is introduced, the curing ovens are no longer sufficient, but either the furnaces must be expanded or the production capacity significantly reduced. As an alternative, it has been proposed to first prepare a phenolic resin bonded mineral wool product, which is then treated at least on the side to be exposed to a high temperature with an inorganic binder which is then pressed or sucked into products. However, this implies that a further production process is obtained.

In the method of the present invention, the so-called "cork chamber technique" is used for the production of mineral wool webs, in which technique a relatively thin primary web is produced which, in layering, especially in folding, forms a relatively thick secondary web in several layers. mineral wool webs are significantly different from the so-called "long chamber technique", which among other things. is described in DE Patent No. 155,897.

From SE C 452.040 and SE C 452.041 it is known to use the above-mentioned choric chamber technique for the production of mineral wool webs, in which the invention according to these patents has sought as uniform an impregnation as possible of the mineral wool webs.

The invention is based on the recognition that there is some correspondence between a point at the beginning of the fiber suspension on its path towards the receiving organ and a larger or smaller area on the surface of the receiving member with a certain portion of the fiber suspension as found initially. of its range of motion. Similarly, a certain portion of the surface of the receiving member can be interconnected and a certain portion of the finished product.

The invention thus relates to a method of applying binder to newly formed mineral wool fibers by means of a plurality of distributing means, e.g. nozzles or spreaders, while suspended in an air or gas stream and on the way to a collection stream. device in which the mineral wool fibers are first collected on a thin web, the primary web which is then added together, e.g., by folding, to a thicker, finished web so that one edge of the primary web forms the top layer of the finished web and the other edge then-5 The lower layer of the web, which is characterized in that binder or binder mixtures of different types and optionally with different dosages are applied to different parts of the fiber suspension, so that different layers in the thickness of the finished web will contain different binders or different binder mixtures and optionally also different binder contents and where the 10 or parts of the fiber su the suspension, which forms one longitudinal side edge of the primary web or both the longitudinal side edges of the primary web, is provided with a different binder than that which is otherwise applied to the suspension.

Thus, with the present method according to the invention, a solution is given to the problem of being able to provide different amounts and different types of binder in different parts of the final mineral wool web.

When the finished web, as stated above, is formed by merging one or more thin webs, so-called primary webs, there is a connection between the edges of the primary web and the top and bottom layers of the finished product. It is thus possible, as stated above, to give the part of the fiber suspension lying on one edge of the primer web a special additive instead of or in addition to the main binder. The additive will then end up in the top or bottom layers of the finished web, depending on which edge of the primary web is being treated.

It is particularly interesting that in this way it is possible to give different properties to one or both outer surfaces. Examples are already mentioned above -25 for. Other examples of such properties that can be altered by providing an outer surface with a different binder are color, dust release, water repellency or water uptake ability.

However, in accordance with the invention, the second outer layer can also be affected by the addition of another binder.

The outer surface (s) thus altered by special additives may therefore not contain the same binder as the rest of the product, namely the main binder. If both outer layers are equipped with different additives, the nature of these and the content of the same as well as the thickness of the layers may be identical or different.

In the cases where the primary path is formed on the receiving means in one step from a fiber suspension which in the initial course moves substantially horizontally, and which is placed on a horizontal or inclined upwardly inclined conveyor, a so-called long-chamber process , it is usually the upper part of the fiber suspension of the fibrating device which also forms the upper part of the primary web, ie. the top surface or layer of the product. Similarly, as a rule, the lower portion of the fiber suspension rests on the receiving member as the lower layer of the primary path, i.e. the other outer surface or layer of the product.

In the case where the primary web is built up by multiple fibrous means successively attaching its fibers to the receiving member, it is so that the first fibrous member substantially forms the lower layer of the primary web and the last member forming the upper layer.

It has been found advantageous to compress the thus-treated primary web. This may conveniently be done by means of a roller or nozzle which presses against the primary web from the edge and a distance towards the center, preferably 10-20 cm.

Similarly, one can identify the portion of the fiber suspension which is generally built up as part of the product and add a special binder or other additive to that portion. If the additive to a certain layer is another binder, it is possible to either maintain the supply of the main binder to the layer or omit this feed. However, it is generally appropriate to allow the main binder to be present throughout the finished web, even if another binder is applied to a particular layer 20 or layers.

The invention will then be explained in more detail with reference to FIG. 1-5. In the drawing FIG. 1 is a side view of a single step mineral preparation mat. In FIG. 2 is a rear view detail of a plant for making a mineral wool mat when laying in bays; and in FIG. 3 is a side view of the same plant 25. In FIG. 4 is a modified plant for manufacturing a mineral wool mat. In FIG.

5a and 5b are diagrammatically a cross-sectional view of the direction of the mineral wool mat through five different parts of the mineral wool mat in two different forms.

In FIG. 1 is a schematic representation of the lower part of a melting plant 1 and a melt which continuously flows out through a gutter 2 and down on a spinning wheel 3 in the form of a jet 4.

The spinning wheel 3 is driven by a shaft 5 enclosed in a sheath 6. Around the spinning wheel 3 there is an air flow 7. The air flow runs around the spinning wheel, but is shown only on the underside for clarity. When the melt from the melting jet 4 hits the spinning wheel 3, it wets but is thrown due to centrifugal force and forms fibers 8. The fibers are thrown outwardly in the plane of the wheel, but their path is deflected by the airflow 7.

The fibers are transported by the air flow to a collection belt 9, for example a perforated steel belt running in a direction indicated by an arrow 10 over rollers 11 and 12. Behind the steel belt there is a suction device 13 in which a negative pressure is created by means of a blower system. . The fibers are laid in the form of a mat 14 which is carried away by the band 9 as indicated by an arrow 15.

In FIG. 2 is shown how a thicker mat is formed by folding a thinner mat. In FIG. 2, reference numeral 16 denotes a thin mat produced 10, for example, as in FIG. 1, mat 14. The mat 16 is advanced on a belt conveyor 17 to a so-called pendulum. The pendulum consists of two belt conveyors 18 and 19, between which the mat 16 is substantially lowered downwards. The conveyors 18 and 19 are pivotally mounted at their upper end, while the lower end moves rhythmically back and forth across a transverse receiver conveyor 20 moving at substantially lower speed than conveyors 17, 18 and 19. Thereby the mat is loaded into bays 21 .

In FIG. 3 is a side view of the same construction in simplified form. The mat 16 moves downward as indicated by an arrow 22 between the conveyors 18 and 19 (not in Fig. 3). The mat is thereby laid on the conveyor 20 in the bays 21. which will partially cover each other as indicated in FIG. 3. The one edge portion of the primary web forms the one outer layer of the new web, while the other edge portion forms the other outer layer.

The mat, which is now formed by the bays 21, thanks to the properties of the mineral wool web 16, forms a substantially continuous but substantially thicker web than the mat 16.

The mat is then passed on to systems for compressing and curing the binder etc.

In FIG. 4 is shown in principle a plant for forming and collecting a mineral wool web. From a melting plant 24, the melt runs into a split melting ring 25 and is thus distributed on two spinning wheels 26 and 26 '. Part of the melt is transmitted secondary to spinning wheels 27 and 27 '. The spinning wheels rotate quickly by means of drive shafts not shown in the figure. From the spinning wheels, the melt is thrown outwards in the form of fibers which, under the influence of air currents 28 and 28 'leading around the spinning wheels, are advanced to a collecting band 29 as indicated by arrows A, B, C, D and E. From so-called central spreaders 30 , 31, 32 and 33, binder is released which impinges on the fiber currents A - E. The fibers are delivered from various locations on the periphery of the spinning wheels. Only the fibers moving in the horizontal plane through the spinning wheel shafts are shown in the figure. Against the flow stream A, a stream of binder 34 is directed from a nozzle 35, which binder is supplied via a conduit 36. Against the fiber stream E, a binder stream 37 is directed, which stream is supplied from a channel 38 which opens in the opening 39 in a wall 40. The binder flow 37 is produced by a nozzle 41 applied to the binder through a conduit 42 and compressed air through a conduit 43.

The fiber streams A-E move toward the collection belt 29 as a result of a negative pressure produced by a not shown suction device on the underside of the collection belt. Fiber flow A thereby falls substantially at the region F of the band, while fiber flow B falls at region G, etc. In this connection it should be noted that no precise delimitation between the fiber currents does not occur. Usually there is always some turbulence, which causes the fiber currents to mix with each other without creating any sharp boundaries. Thus, between the areas F and G of the band there is also a mixture of the fibers from the fiber streams A and B etc.

All means for adding binder, central spreaders 30, 31, 32 and 33, nozzle 35 and nozzle 41 can hereby supply separate binder types and thereby deliver separate binder types with individual dosage. Usually, the central spreaders are supplied with the main binder, which is usually a phenolic resin. Advantageously, suspensions of inorganic binder such as bentonite suspended in water can be added through the rear nozzles such as the nozzle 35. At the intense heat of the melting ring 20 on the spinning wheel, the water is evaporated at an early stage, which reduces the later drying need, without hampering the process of distribution. On the other hand, if one wants to add a blank or agent, for example an organic dye that is water sensitive, this is advantageously done in a nozzle, such as the nozzle 41, in which the addition and the finely divided blank represented by the reference numerals 37, 25 are spared a too high temperature.

If the main binder in a structure such as that of FIG. 4 is dispensed from the central spreaders 30-33, while adding another binder from nozzle 35 and another item from nozzle 41, a binder amount can be obtained as shown in FIG. 5a plotted after a horizontal axis at various locations in the width direction of the collecting tape 30. The letters F, G, Η, I and J correspond approximately to the locations indicated in FIG. 4. The vertical axis indicates the quantities of mineral wool additive. The meaning of the markings is found in the figure. If all the central spreaders 30-33 are dosed in the same way and with the head binder, the head binder appearance is distributed evenly throughout the mineral wool mat.

6 DK 173106 B1 In the example shown, a second binder is supplied via the nozzle 35, and this binder is found as an addition to the main binder in the main site F and with some spread towards the site G. The additive, e.g. via the nozzle 41, is found at site J with some overlap with site I.

5 In FIG. 5b is shown another example, according to which the central spreaders 30 and 33 have considerably less dosage than the central spreaders 31 and 32. In contrast, larger quantities are supplied via the nozzles 35 and 41 than in the above example. This results in a completely altered distribution of additive to the mineral wool as shown in FIG. 5b.

10 It will immediately be seen that in this way it is possible to produce a virtually unlimited amount of variants. For each specific field of application where only a single head binder is not sufficient to give the desired properties to the products, a dosing characteristic can be produced to meet the requirements or requirements.

In FIG. 5a and 5b are shown only the amounts within certain parts of the mineral wool dimension. This is not to be understood in that the main binder is separate from the second binder. Of course, within the area F, both the main binder and the second binder occur within the entire mat. Similarly, within the area J, the main binder and other additive are found throughout the mat.

20 The diagrams show only the relative quantities.

Of course, it may be necessary that a nozzle corresponding to the nozzle 35 is located on the other side so that even the fiber stream E is fed with additive from such a nozzle. Similarly, a nozzle corresponding to the nozzle 41 may be needed, on the other hand, thereby affecting the fiber flow A and the location F. Similarly, nozzles 25 corresponding to the nozzle 35 may be located at different locations relative to the fiber plant not only at the flanks.

The nozzles 35 and 41 are described in the description above as single nozzles. However, there is nothing to prevent, and it is often appropriate to use multiple nozzles instead of a single nozzle so that the binder supply does not occur too concentrated within a single range.

As an example of the use of the invention, an experiment has been described herein which has been carried out in connection with machine arrangements similar to those in FIG. 1, 2, 3 and 4. At a production rate of 4,000 kg / h, through each central nozzle 30-33 250 l / h was passed in each nozzle. Through the nozzle 35, 1,600 l / h of a 35 bentonite slurry with 7% solids content was passed. The main binder is a phenolic resin having a solids content of approx. 20%. This gave a binder content of the product of approx. 3.5% by weight calculated on the basis of phenolic resin. In the upper layer of the product there was abundant bentonite. However, it was difficult to determine the exact quantities. The products had excellent shelf life and even after the bentonite infused was exposed to temperatures of 400 ° C, at which temperatures the phenolic resin content rapidly burned, the products still had sufficient durability to handle the products.

In another experiment, through the central nozzles 30-33, 1,200 l / h was passed through. nozzle of bentonite slurry, while from three pcs. nozzles 35 placed over each other 10 were passed phenolic resin at a rate of 200 l / h. The mineral wool thus impregnated could only be handled with some difficulty. After curing and drying, it had satisfactory properties in terms of durability. This was also the assessment after the side which did not contain phenolic resin had been exposed to a temperature of 500 ° C for 10 hours. Prior to the heat treatment, it was found that the one side, which was equipped with phenolic resin, had a significantly better handling durability than the side in which the binder consisted solely of bentonite. After the heat treatment, the product's durability properties were satisfactory.

Claims (8)

10 DK 173106 B1 A method of applying binder to newly formed mineral wool fibers by means of a plurality of distribution means, e.g. nozzles or spreader (30-33, 35,41) while suspended in an air or gas stream (7; 28, 28 ') and is on its way to a collection device (29), wherein the mineral wool fibers are first collected into a thin web, the primary web (16) which is then joined together, e.g. by folding, to a thicker finished web (21) so that one edge of the primary web forms the top layer of the finished web, and the second edge forms the bottom layer of the web, characterized in that binder 10 or binder mixtures of different types and optionally with different dosages are applied to different parts of the fiber suspension so that different layers in the thickness of the finished web will contain different binders or different binder mixtures and optionally also different binder contents, and wherein the portion (s) of the fiber suspension forming the primary base one longitudinal side edge or both longitudinal side edges of the primary web is provided with a different binder than that which is otherwise applied to the suspension. Process according to Claim 1, characterized in that the binder of another part of the fiber suspension which after folding by folding the primary web forms the upper or lower surface of the finished web, is provided by one or more special distribution means. type than the binder, the main binder applied to the portion of the fiber suspension, which generally forms the remainder of the finished web. The method according to claim 1, characterized in that the binder of a type other than the one or more special distribution means which, after being folded by folding the primary web generally forms the upper or lower side of the finished web, is applied to a binder of a different type. the binder, the main binder, which is applied to the portion of the fiber suspension which generally forms the remainder 30 of the finished web. Method according to claim 1, 2 or 3, characterized in that the edge (s) of the primary web (16) containing a different binder than the main binder is compressed, for example by means of a roller or roller, before the primary web 35 (16) is added to a finished track (21). 11 DK 173106 B1 Method according to any one of the preceding claims, characterized in that a binder other than the main binder is applied to the part of the fiber suspension which, after being folded by folding the primary web in the main saw, forms the upper or lower side of the finished web. and, further, a binder other than the main binder is added to the portion of the fiber suspension which forms substantially the underside or top side of the finished web, respectively. Process according to any of the preceding claims, characterized in that the binder contents in both the upper and lower sides of the finished web are different, and preferably also have a different binder content than the binder content in the rest of the web. Process according to any one of the preceding claims, characterized in that the main binder is applied to all parts of the fiber suspension, so that in the layers where a second binder is present, there is a main binder in addition to this second binder. Process according to any one of the preceding claims, characterized in that the main binder is organic, for example a phenolic resin and that at least a part of the fiber suspension which forms essentially the outer layer of the finished web is applied to an inorganic binder, e.g., a clay suspension.