FI98213C - Method for conducting binders on mineral wool - Google Patents

Description

5,98213

Method for deriving binders from mineral wool Sätt att föra bindemedel account mineralull 'Mineral wool products are usually produced by producing mineral melt in a smelting unit from which the melt is transported. continuously into the defibering unit. In the defibering unit, the melt is converted into large or small fibers which are conveyed by air or kaa-10 flow from the defibering unit to a receiving member in the form of a perforated conveyor, on which the fibers form a continuous path as air or gas flows through the conveyor

15 The raw materials may consist of stone or slag, in which case domed furnaces are usually used as smelting units. The defibering then takes place quite often with rapidly rotating, internally water-cooled steel cylinders, the so-called spinning wheels, arranged to receive the melt in succession. The melt is thus fed to one of the 20 wheels, which throws it further to the next wheel, etc. Such an arrangement is called a cascade spinning method or JM process (Johns-Manville). The number of spinning wheels in the cascade is usually 2-4. More than four spinning wheels are quite rarely used in a cascade.

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In order to achieve higher capacity, parallel defibering equipment is sometimes used. Most commonly, two identical defibering devices or two defibering devices are used in parallel, which are mirror images of each other and between which the melt is distributed.

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In the manufacture of glass wool, more or less conventional glass raw materials are used, which are usually melted in a bath. According to the most commonly used fiberization method, the melt is then allowed to flow downward into a plurality of hollow centrifuges 35 rotating about perpendicular axes. The centrifuge casing has holes through which centrifugal force compresses the thin strands of the molten glass, the so-called primary fiber 2 CP.9 Ί; y ^ e. i vj jen, in the form. The defibering itself is performed by strong, axially directed flows of gas or air flowing past the mantle surfaces of the centrifuges.

5 Air currents are also used around the spinning wheels when defibering stone or slag wool. The air streams have several functions: for example, they transport the fibers from the defibering member itself towards the collecting member, whereby the fibers settle on the collecting member as mentioned above as the gas or air flow passes through them.

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In the commercial manufacturing processes of mineral wool products, this gas or air stream occurs purely in principle, in which the fibers formed in the stream are more or less well suspended and which stream carries the fibers from the defibering device to the receiving member. If a binder is introduced into the mineral wool, as is practically always the case, this is most often done by adding a fine binder to this fiber suspension. Instead of or together with the binders, other ingredients, such as a wetting agent or a dust-binding agent, can also be added to the fiber suspension. Addition 20 is often performed very close to the defibering member itself. The reason that the binder is introduced into the fiber suspension and not into the continuous web formed on the receiving member is that the binder is difficult to penetrate the mineral fiber structure due to the density of the structure and the fineness of the fibers relative to the size of the binder droplets.

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There are two mainly different principles for the operation of the receiving agency. According to the second principle, i.e. originally used, a final track is built on the conveyor of the receiving member, which travels forward for hardening, cooling, splitting, cutting, etc. This means, in technical terms, that the basis weight, e.g. g / m2, is already for the permeable conveyor the same as later in the final product. However, there is another principle that in many cases achieves a better result. According to this principle, a relatively thin track, the so-called the primary web, which is subsequently constructed after folding in one or more stages 3 9821ο into a final web with a surface pressure corresponding to the finished product. surface weight. The basis weight of the primary track can in many cases be much lower than the basis weight of the final track, e.g. one tenth or less.

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The air or gas flow which transports the fibers from the defibering device to the receiving member is more or less turbulent. However, studies have shown that when the journey is not particularly long, no complete mixing occurs. This means that the fibers 10 routed to this air or gas stream from a particular point tend to settle primarily at a particular location or area of the receiving conveyor, while the fibers routed to the air or gas stream from another point tend to settle primarily to another area. This finding has been exploited in connection with the invention.

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The binder used in mineral wool products is usually organic. In exceptional cases, phenolic plastic is used, which may, however, be more or less modified. However, mineral wool can withstand higher temperatures than an organic binder. However, in certain applications, such as mineral wool insulation used in stoves or ovens, there are two disadvantages, both due to the inability of the binder to withstand the temperatures present.

Another disadvantage is that gases and smoke are generated when the binder burns, which causes e.g. smoke problems.

Another disadvantage is that the binder-free wool does not subsequently have the firmness that may be required by the application. Therefore, attempts have been made to find more heat-resistant binders, which are preferably inorganic. However, it is very difficult to find an inorganic binder that can give products the same flexibility and shape retention as plastic binders. In addition, most binders require the use of fairly large amounts of water, which in turn causes drying problems. Most of the devices for the production of mineral wool 35 are adapted to use a plastic binder which can be fixed in a very short time in the so-called

4,98213 in tempering furnaces. When a water-based, inorganic binder is used, tempering furnaces are not sufficient, but the furnaces must be converted or the production capacity must be significantly reduced. It is also contemplated that, alternatively, a phenolic resin-bonded mineral wool product is first prepared and subsequently treated, at least on the side exposed to the high temperature, with an inorganic binder that is pressed or absorbed into the product. However, this means one additional production process.

The invention is based on the idea that at the beginning of the fiber suspension, between a point advancing towards the receiving member and a larger or smaller area on the surface of the receiving member, there is a certain correspondence with a certain part of the fiber suspension when the suspension is at its beginning. Similarly, a portion of the surface of the receiving member may be joined to a particular portion of the final product. This is utilized according to the invention in that different binders or binder mixtures are introduced into different parts of the fiber suspension, possibly in different doses, so that the different layers in the finished web or product contain different binders or binder mixtures and possibly also different binder concentrations.

For the method according to the invention, in which the binder is added to the newly formed mineral wool fibers by means of a plurality of distribution means, such as nozzles or spreaders, suspended in an air or gas stream and on the way to a collector. that one edge of the primary web forms the upper layer of the final web and the other edge of the lower layer, it is characterized in that different binders or binder mixtures are added in different portions to different parts of the fiber suspension so that different layers in the thickness direction of the finished web contain different binders or binder mixtures, and possibly also different binder concentrations, in which part or parts of the fiber suspension which form or form one or both edges of the primary web, a binder other than that otherwise used in the suspension is added.

98213 5

It is of particular interest that modified properties can be imparted to the second surface layer or both surface layers of the product. Examples of this are given above. Other examples of such properties that can be modified by providing the surface layer with a second binder are color, dustiness, water repellency and water absorption properties.

According to the invention, the second surface layer can also be affected by applying a second binder to it.

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The surface layer or surface layers thus modified with different additives may additionally contain the same binder as the other product, i.e. the main binder. If both surface layers are provided with different additives, the type and concentration of the substance and the thickness of the layers may be the same or different.

When the final product is formed on the receiving member in one step from a fiber suspension, which initially moves mainly horizontally and deposits on a horizontal or obliquely upwardly inclined conveyor 20, in which case it is a so-called from the longitudinal chamber process, the upper part of the fiber suspension near the defibering device generally also forms the upper outer layer of the final product. Similarly, the lower portion of the fiber suspension deposited on the receiving member generally forms the lower outer layer of the final product.

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If the final product is constructed in such a way that several defibering members supply their fibers one after the other to the receiving member, the first defibering member then mainly forms the lower layer of the final product and the last member forms the upper layer.

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When the final path is formed by connecting one or more thin paths, i.e., the primary path, there is a connection between the edges of the primary path and the upper and lower edges of the final product. A portion of the fiber suspension deposited on the other edge of the primary web can be fed with a special additive instead of or in addition to the main binder. The additive then enters the upper or lower layer of the loose web, depending on which edge of the primary web is treated.

It has been found that a better effect is obtained by pressing the edge of the primary track thus treated. This is preferably done by means of a roller or roller which is pressed against the primary track from the edge and the distance of the piece towards the center, preferably 10-20 cm.

Similarly, the portion of the fiber suspension that essentially forms a particular portion of the product can be identified and a specific binder or other additive added to that portion. If the additive of a particular layer is another binder, the main binder may be added to that layer or omitted. In general, however, it is advantageous for the main binder to be present throughout the final web, even if a second binder is added to a particular layer or layers.

The invention will now be described in more detail with reference to Figures 1-5. Figure 1 is a side view of an apparatus for making a mineral wool mat in one step. Fig. 2 shows a rear view of a detail 20 of a device by means of which a mineral wool mat is produced by pleating, and Fig. 3 shows the same device seen from the side. Figure 4 shows a modified device for making mineral wool. Figures 5a and 5b show in diagrammatic cross-section of the mineral wool against the direction of travel of the mineral wool from five 25 different parts according to two different alternatives.

Figure 6 schematically shows a side view of an alternative further embodiment of a device for manufacturing mineral wool.

Fig. 1 schematically shows the lower part of the melting device 1 and the melt flowing continuously downwards through the trough 2 in the form of a thread 4 for the spinning wheel 3.

The defrosting device can be selected from several different types of equipment, 35 and is therefore only referred to. The spinning wheel 3 is driven by a shaft 5 surrounded by a jacket 6. An air flow 7 flows around the spinning wheel 3.

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The airflow passes around the spinning wheel, but it is shown below only for clarity. When the melt of the melt strand 4 encounters the spinning wheel 3, it wets but is ejected by centrifugal force and forms fibers 8. The fibers are ejected out in the plane of the wheel, 5 but the air flow 7 bends their course.

The air stream conveys the fibers towards the assembly belt 9, e.g. the torn steel strip, which passes in the direction 10 through the rollers 11 and 12. Behind the steel strip is a suction box 13 into which the ventilation system creates a vacuum. The fibers are deposited to form a mat 14, which carry the strip 9 in the direction of the arrow 15.

Figure 2 shows how a thinner mat is formed by folding a thicker mat. In Fig. 16, the number 16 refers to a thin mat 15 provided, for example, in the same manner as the mat 14 in Fig. 1.

The mat 16 passes by a belt conveyor 17 ns. the pendulum. The pendulum consists of two belt conveyors 18 and 19, between which the mat 16 is conveyed mainly downwards. The conveyors 18 and 19 are pivotally mounted at their upper end, while the lower end moves rhythmically back and forth by a transverse receiving conveyor 20 which moves at a significantly lower speed than the conveyors 17, 18 and 19. In this case, the mat is layered in folds 21.

Figure 3 shows the same in a simplified form when viewed from the side 25. Carpet 16 moves downwards according to arrow 22 between the conveyors 18 and 19, which are not shown in Fig. It is then deposited on the conveyor 20 in folds 21 which partially overlap, as shown in Fig. 3. The second edge portion of the primary track forms the second surface layer of the new track, while its second edge portion forms the second surface layer.

Due to the properties of the mineral wool web 16, the mat now formed by the pleats 21 forms a largely continuous, albeit substantially thicker web than the mat 16. It then travels 35 forward to an apparatus where the binder is compressed and hardened, etc.

8 o O O Ί 7> oz ίό

Figure 4 shows in principle an apparatus for forming and assembling a mineral wool web. From the melting device 24, the melt flows downwards along the divided melting trough 25 and is thus divided into two spinning wheels 26 and 26 '. A portion of the melt is secondary transferred to the crankshafts 27 and 27 '. The spinning wheels rotate rapidly by means of drive shafts not shown in the figure. From the spinning wheels, the melt is ejected outwards in the form of fibers which travel forward under the action of the air currents 28 and 28 'surrounding all the spinning wheels towards the spinning belt 29, as indicated by arrows A, B, C, D and E. From the so-called center plates 10,31,32 and 33, a binder is fed which meets the fibers A-E.

The fibers leave different points on the circumference of the spinning wheel. Only those fibers that move horizontally through the axes of the spinning wheels are shown in the figure. The flow of binder 34 from the nozzle 35, which is fed through the line 36, is directed against the fiber stream A. The binder stream 37 flows against the fiber stream E and flows from a duct 38 leading to an opening 39 in the wall 40. The binder stream 37 is produced by a nozzle 41 to which a binder is fed via a line 42 and compressed air via a line 43. The fiber streams A-E move towards the collection belt 29 under the effect of the vacuum produced by the suction box (not shown) on the back side of the collection belt or below. The fiber stream A then enters mainly the region F of the strip, the fiber stream B the region G, etc. In this case, it should be noted that no precise boundary is created between the fiber streams. Normally, there is always a certain turbulence, which causes the fiber streams to mix with each other, and no precise boundaries are created. Thus, between the regions F and G of the strip 25, a mixture of fibers of the fiber streams A and B enters, etc.

All binder feed members, center spreaders 30, 31, 32 and 33, nozzle 35 and nozzle 41 can now be fed separately, allowing different types of binder to be added in different doses. The main binder 30, which is usually a phenolic resin, is normally fed to the center spreaders 30.

Suspensions of inorganic binders, such as bentonite slurried in water, can be easily added by means of rear nozzles 35. The high heat generated by the melt ring of the spinning wheel evaporates the water at an early stage, which reduces the need for subsequent drying 35 without compromising the fine grinding process. If it is desired to add a substance, e.g. an organic dye, which is heat-sensitive, it is fed, for example, to a nozzle such as a nozzle 41, in which the additive itself and the fines referred to by the number 37 are saved from too high a temperature.

If an arrangement according to Fig. 4 is used, in which the main binder is dispensed from the center applicators 30-33 and the second binder is additionally fed from the nozzle 41, the amount of binder shown in Fig. 5a along the horizontal axis can be obtained at different positions in the width of the assembly strip. The letters F, G, H, I and J correspond approximately to the positions shown in Fig. 4. The vertical axis shows the amount of additive fed to the mineral wool. Explanations of the columns are given below the figures. If all the center spreaders 30-33 are dosed in the same way and a main binder is fed to them, the main binder is relatively evenly distributed throughout the mineral wool.

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The second binder is added in the example through the nozzle 35 and is present in addition to the main binder mainly at position F and slightly spread towards point G. The additive, in the example the dye added through the nozzle 41, remains in position J slightly withdrawn towards position I20.

Figure 5b shows the same example, but with significantly less dosing of the center spreaders 30 and 33 than with the center spreaders 31 and 32. In contrast, larger amounts are fed to the nozzles 35 and 41 than in the previous example. The additive is then distributed in a completely different way with the mineral wool, as shown in Figure 5b.

It is easy to see that an almost unlimited number of variations can be achieved in this way. In any particular field of application where the main binder 30 is not sufficient to give the products the desired properties, the dosing can be arranged in a way that meets the requirements.

Figures 5a and 5b show only the amounts in the corresponding part of the mineral wool. This is not to be understood as meaning that the main binder si-35 is separate from the other binder. Area F actually contains both the main binder and the other binder throughout the mat. In the district J

10 90212 is similarly the main binder and other additive throughout the mat. Only relative amounts are shown in the graph.

It may, of course, be required that the nozzle corresponding to the nozzle 35 also be arranged on the other side so that the fiber stream in the region E receives an additive from such a nozzle. A nozzle corresponding to the nozzle 41 may be required in the same way on one side to influence the fiber flow A to the position F. The nozzles corresponding to the nozzle 35 can be placed at different points relative to the defibering device, respectively, and not only on the sides.

Figure 6 shows an example of the so-called pitkittäiskammiolinjalla. The air stream 7 conveys the fibrous stream 8 provided with the binder 44 over the threshold 45 to the chamber 46. There it falls and is absorbed downwards towards the belt 47, 15 under which a suction box 48 is arranged. through a roll 49 which partially protrudes below the threshold 45. The tape moves in the direction of arrow 50 direction, and the tape is deposited on increasing the mineral wool so that the thickness increase of the chamber toward the outlet 51, wherein the sealing of the chamber end 52 against occurs kammiotelalla 53. It can be shown, 20 and the upper part of the outgoing mineral wool layer 54 is mainly derived from the fibers that come from the chamber 46 near its ceiling 55, while the part of the mineral wool layer closest to the strip 47 originally comes from the lower part of the defibering device and flows into the chamber near the threshold 45. If another binder 25 is to be added to the other surface of the product, it is recommended to add it below. The second binder is then passed from line 58 through a nozzle 57 to be fed. The stream of binder particles exiting the nozzle 57 meets the lower portion of the binder stream 44 and enters the very bottom of the product, as described above.

Nozzles 35, 41 and 57 are mentioned in this description as individual nozzles. However, it is possible and often useful to use several nozzles instead of one nozzle so that the binder dose is not concentrated too much in one area.

As an example of the application of the invention, an experiment related to the machine arrangements of Figures 1, 2, 3 and 4 will now be described. With a production volume of 11 C P 0Ί; ΙΟ 250 kg / h was delivered to each nozzle via center spreaders 30-33 to 250 n / a. Bentonite slurry 1600 l / h with a dry matter content of 7% was sent through nozzle 35. The main binder consisted of phenolic meat resin with a dry matter content of about 20%. The permeable binder content of the product was then 3.5% by weight, calculated on the phenolic resin. The top floor of the product was rich in bentonite. However, the exact amounts were difficult to determine. The products had excellent durability, and even after the concrete-covered side was brought to a temperature of 400 ° C, whereby the phenol-10 resin burns off rapidly, the product retained sufficient durability properties to be treated.

In the opposite experiment, 1200 1 / h of concrete slurry was sent through each nozzle through the center spreaders 30-33, and 200 1 / h of phenolic resin was sent from the three overlapping nozzles 35. Mineral wool impregnated in this way was quite difficult to harden. However, after hardening and drying, it had satisfactory durability properties. The result was the same even after the half which did not contain phenolic resin was at 500 ° C for 10 to 20 hours. Prior to the heat treatment, it could be found that the phenol resin-treated side had substantially better treatment resistance than the side with only bentonite as a binder. After heat treatment, the durability properties of the product were satisfactory.

25 12 96-215

The reference numbers

Figure 1: Figure 4, continued: 1 melting device 29 collecting belt 2 chute 30 center spreader 3 spinning wheel 31 center spreader 4 thread 32 center spreader 5 shaft 33 center spreader 6 jacket 34 binder 7 air flow 35 nozzle 8 fibers 36 wire 9 11 roll 39 opening 12 roll 40 wall 13 suction box 41 nozzle 14 mat 42 wire, binder 15 (directional arrow) 43 wire, binder

Fig. 2 and 3: Fig. 6: 16 carpet, thin 44 binder 17 belt conveyor 45 threshold 18 belt conveyor 46 chamber 19 belt conveyor 47 belt 20 receiving conveyor 48 suction box 21 pleats 49 roll 22 (directional arrow) 50 (directional arrow) 51 outlet (chamber)

Figure 4: 52 chamber end 53 chamber roll 24 melting device 54 top (part 6) 25 chute 55 chamber roof 26 spinning wheel (26 ') 56 mineral wool layer 27 spinning wheel (27') 57 nozzle 28 air flow (28 ') 58 line

Claims (9)

1. Use a plurality of distribution means, e.g. nozzles or sprinklers (30-33; 34.41; 57), adding binders to newly formed mineral wool fibers while suspended in an air or gas stream (7; 28.28 ') and on their way to a collection device (29; 47) , where the mineral wool fibers are first collected into a thin web, the primary web (16), which is later joined together, e.g. by folding, to a thicker, final web (21), such that one edge of the primary web forms the overlay of the final web and the other edge forms its lower layer, characterized in that adhesives or adhesive mixtures of various kinds and possibly with different dosages are added to different portions of the fiber suspension so that different layers in the thickness direction of the finished web may contain different adhesives or binder mixtures and possibly also different binder contents, the part or parts of the fiber suspension forming the primary longitudinal side edge and the bed of the primary web, respectively. side edges are applied to a different binder than that which is applied to the suspension in general. 20 2. A method according to claim 1, characterized in that the part of the fiber suspension which, after being combined by folding, essentially forms the upper or lower layer of the final web, through one or more distributing means, is provided with adhesives other than that adhesive, the main adhesive, which is applied to the portion of the fiber suspension which essentially forms the remainder of the final web. 3. A method according to claim 1, characterized in that the parts of the fiber suspension which, after being combined by folding, essentially form the top and bottom layers of the final web, are bonded to another adhesive of the same kind or to the binder, the main binder, by one or more special distribution means. which is applied to the portion of the fiber suspension which essentially forms the rest of the final web. k 4. A method according to claim 1,2 or 3, characterized in that the edge (s) of the primary web (16) containing a different binder part than the main binder is compressed, e.g. with a roller or roller, before the primary web (16) is combined into a final web (21). 5. A method according to any of the preceding claims, characterized in that a binder other than the main binder is added to a portion of the fiber suspension after aggregation by folding the primary web mainly forming the final web's overlay or undercoat and that another binder other than the main binder is added. the portion of the fiber suspension which essentially forms the bottom layer 10 of the final web, respectively. topsheet. 6. A method according to the preceding claim, characterized in that the binder content in the top and bottom layers of the final web is different, and preferably also has a different binder content than the binder content in the rest of the web. 7. A method according to any 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 another binder is present, the main binder 20 is in addition thereto. 8. A method according to any of the preceding claims, characterized in that the main binder is organic, e.g. a phenolic resin resole, and that at least one of the portions of the fiber suspension which forms substantially the outer layer of the final web is provided with an inorganic binder, e.g. and clay suspension.