SK45896A3 - A method of producing a non-woven mineral fiber web, a device for producing non-woven mineral fiber web and a mineral fiber product - Google Patents

Abstract

In a method of producing a non-woven mineral fiber web, mineral fibers are produced from a mineral material by means of a mineral fiber generating means. The mineral fibers are transferred from the mineral fiber generating means by means of a carrier air stream, and droplets and/or particles of a bonding agent or coupling agent is introduced into the carrier air stream for causing the mineral fibers to be bonded or linked together. In order to eliminate waste of bonding agent or coupling agent material, the droplets and/or particles predominantly have diameters larger than a minimum diameter corresponding to a droplet and/or particle showing substantially no tendency to impact the mineral fibers of the carrier air stream.

Description

Non-woven non-woven non-woven non-woven mineral fiber web, mineral fiber machine and product

Technical field

The invention relates generally to the field of production of mineral fiber insulation boards. Mineral fibers generally include fibers such as mineral wool fibers, glass fibers, etc. More specifically, the invention relates to a new technology for producing a mineral fiber insulating web from which for example insulating boards or mineral fiber products are punched. The insulating boards or products obtained from the mineral fiber insulating web produced according to the invention exhibit advantageous mechanical properties such as modulus of elasticity and strength, low weight, reduced binder content and good thermal insulation properties.

BACKGROUND OF THE INVENTION

Mineral fiber insulating webs are typically manufactured as mineral fiber webs that are ejected from the mineral fiber generating device and transmitted by air flow to a collecting conveyor. The mineral fibers of which the insulating web is composed are usually interconnected by means of droplets and / or particles of a heat-curable binder which are cured upon exposure to heat. For the formation of a mineral fiber web with adequate mechanical properties and mechanical integrity, such as flexibility and strength, some cured binder must be present. Until now, an excess binder has been used to achieve adequate mechanical properties and integrity, for example in an amount of the order of 10 to 30% by weight of the mineral fiber binder.

Conventional methods of producing mineral fiber insulating webs that are carried by an air stream from a mineral fiber generating plant to a collecting conveyor are associated with serious waste or environmental problems because the air stream through which the mineral fibers are transferred from the mineral generating plant The mineral fibers for the collecting conveyor contain a plurality of droplets and / or particles of a thermosetting binder. The tick does not separate the droplets and / or particles of the heat-curable binder that are entrained by the air stream after transfer of the mineral fibers from the mineral fiber generating device to the collecting conveyor from the air which is later discharged into the atmosphere through a chimney or similar. or particles of heat-curable binder that are entrained with air will cause serious environmental pollution.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a new method of producing a mineral fiber web from which mineral fiber products can be produced which substantially reduce the above-mentioned waste or environmental pollution problems.

It is a further object of the invention to provide a new method of producing a mineral fiber web from which mineral fiber products can be produced that radically reduce or substantially eliminate the need to separate excess droplets and / or particles of thermosetting binders that are entrained by the air stream after formation. mineral fleece.

It is a further object of the present invention to provide a new method of producing a mineral fiber web from which mineral fiber products can be produced, which would enable the production of mineral fiber products in a production line having the same structure from the mechanical point of view as prior mineral fiber products. while reducing the amount of binder.

It is a further object of the invention to provide a new method of manufacturing a mineral fiber web from which mineral fiber products can be produced which would enable to produce mineral fiber products with improved mechanical properties, such as modulus of elasticity and strength, over conventional fiber products. mineral fibers with the same binder content.

A particular advantage of the invention relates to the fact that the novel method of manufacturing a mineral fiber web according to the invention makes it possible to substantially remove the thermosetting binder waste from the plant in which it is carried out, further to substantially eliminate environmental pollution problems caused by waste of excess binder or binder. from the device to the environment, and further substantially eliminate the need to separate excess heat-curable binder from the waste air outlet of the device.

A further advantage of the invention relates to the novel mineral fiber product according to the invention, produced by the method according to the invention, which mineral fiber product contains less binder compared to known mineral fiber products and is thus less expensive than prior art mineral fiber products. the existing mineral fiber products have advantages in terms of mechanical and thermal insulation properties.

A further advantage of the invention relates to the fact that the amount of binder used to produce a mineral fiber product of a certain type is reduced by the method according to the invention, since in the mineral fiber product according to the invention it is possible to reduce the binder amount compared to previous mineral fiber products with similar properties. in terms of mechanical strength and thermal insulation properties.

A particular feature of the invention relates to the unique efficient use of a thermosetting binder applied in the form of droplets and / or particles to mineral fibers that are transferred from the mineral fiber generating device by means of an air stream without substantially causing any environmental problems caused by excess binder discharged into the atmosphere.

The aforementioned objects, advantages and specific feature, together with a number of other objects, advantages and features, which will become apparent from the detailed description of preferred embodiments of the invention set forth below, are achieved according to a first aspect of the invention by a method of manufacturing a non-woven mineral fiber web comprising the steps:

melting the mineral material and forming a stream of molten mineral material, guiding said stream of molten mineral material to the mineral fiber forming apparatus to form the mineral fibers by solidifying said molten material, expelling said solidified mineral fiber material in the form of mineral fibers from said mineral fiber forming apparatus, an air stream downstream of said mineral fiber generating device for entraining said mineral fibers from said mineral fiber generating device, forming and spraying droplets and / or binder particles or binding agent on said mineral fibers in said carrier air stream such that said droplets and / or or particles have fallen on said mineral fibers, said droplets and / or particles being predominantly larger in diameter than the minimum diameter of said droplets. conducting a droplet and / or particle substantially free of said mineral fibers in said carrier air stream, and collecting said mineral fibers from said carrier air stream on the collecting surface of the mineral fiber web to form said nonwoven mineral fiber web.

In the context of the invention, the term droplets and / or particles encompasses components of a liquid or solid material of small size, commonly known as droplets and / or particles. particles, but also includes small particles comprising a mixture of liquid or solid material. In the context of the invention, the term average is a general term referring not only to a particular dimension of a sphere, but also encompassing the overall external dimension of any arbitrary body of a specific geometric configuration, including spheres, cubes, ellipsoids, etc. and combinations thereof, and represents a relevant external dimension representing the overall dimensions of the body. The term binder or binding agent in the context of the invention includes any material capable of binding to or bonding mineral fibers to each other or of adhering to each other and further capable of imparting to the mineral fibers before or after bonding to each other any specific characteristic or property, such as are characteristics or properties related to binding ability, affinity, impregnation, such as the ability to absorb / absorb / repel water, and the protection of mineral fibers, etc. Examples of binders or binding agents are thermosetting resins commonly used in the industry for the manufacture of mineral fiber products, and specific types of oils or surfactants capable of imparting specific characteristics or properties.

In the context of the invention, it has been found that droplets and / or particles of a binder or binding agent that are sprayed onto mineral fibers that are entrained by the carrier air stream have a reduced tendency to impact the mineral fibers when the droplet and / or particle diameter is less than a specific minimum droplet and / or particle diameter, determined essentially by the speed of the carrier air stream. In accordance with the terminology used in the field of application of fertilizer by means of a carrier air stream, the criterion of the invention according to which droplets and / or particles of binder or binder sprayed on mineral fibers can be entrained by the carrier air stream is defined as droplets and / or particles with a diameter greater than the specific diameter of the droplets and / or particles, which diameter corresponds to the droplet and / or particle carried at a specific air flow velocity, as is evident from the discussion below. In the above area, it has been found that there is a specific diameter threshold below which particles or droplets that are injected by the carrier air stream are only entrained by the carrier air stream without impinging on any obstacles which characteristic feature is characterized as carrying droplets and / or particles by air.

In accordance with conventional technologies of applying droplets and / or particles of binder or mineral fiber binding agent which are entrained from a mineral fiber generating device by a carrier air stream, which droplets and / or particles may have a diameter in a variable and non-specific range of particle diameters is The invention is based on the finding that droplets and / or particles of a binder or binding agent having a diameter smaller than a specific lower diameter threshold do not tend to impact the mineral fibers entrained

Ným carrier air stream, and thus, as with the fertilizer application technology mentioned above, are lost as carried droplets and / or particles and must be separated from the exhaust air which is discharged into the atmosphere, for example by a chimney or similar device, or the exhaust air is not purified, discharged into the atmosphere, which can, of course, cause serious problems with environmental pollution. Thus, the droplets and / or particles of said binder or binding agent may have a diameter in a range whose lower limit is equal to or greater than said minimum diameter, or alternatively or additionally, the droplets and / or particles of said binder or binding agent may have a diameter within a certain range. wherein the median of said diameter is slightly greater than said minimum diameter and more than 75 to 90%, for example 80 to 95%, preferably 90% of said droplets and / or particles have a diameter greater than said minimum diameter, said minimum diameter preferably being of the order of 10 to 75 μιη, for example 25 to 50 μιη.

In the conventional method of producing nonwoven mineral fiber webs that are entrained by a carrier air stream from a fiber generating device to a collecting device such as a collecting conveyor, the net volume of binder or binding agent used for a particular production can be divided into the first part of the volume those droplets and / or particles that escape as waste, and a second part of the volume corresponding to the droplets and / or particles actually impacting the mineral fibers and used to a greater or lesser extent to interconnect the mineral fibers in the web. Droplets and / or particles that escape as waste may, as will be described in more detail below, be lost for various reasons. Although the droplets and / or particles that make up the aforementioned first part of the volume are substantially smaller than the droplets and / or particles making up the aforementioned second part of the volume, the ratio between the first part of the volume and the total volume used for a particular production may reach of the order of 1 to 2%, which, when compared to the total amount of binders or binding agents used in the mineral fiber industry, can be of a very high value, which in particular causes serious environmental pollution problems if leaking droplets and / or particles they are not separated from the exhaust air vented from the production equipment and, on the other hand, require the use of complex filtration techniques to prevent leakage of the binder or binder into the atmosphere and to raise the above environmental pollution problems.

The process according to the invention can be carried out in accordance with any known production technology, i. mineral fibers can be produced by spinning wheel technology, spinning, mineral fiber nozzle, and the like. Various designs of mineral fiber forming apparatus are known, and reference is made to the following documents, of which US patents are hereby incorporated by reference. These are: DK 158.612, US 4,434,299, EP 0 059 152, GB patent application

9001124.8 (published Jul 18, 1991), GB 1,515,511, GB

GB 2,004,205, GB 2,004,206, GB 2,026,104, GB

GB 2,118,866, GB 2,142,844, GB 93/00053, DD

DK 5318/89, SE 463.817,

2,004.204.

2,043.489.

155,897, SE 452,150, and US 5,123,949.

EP 0 530 843

An example of conventional technology of applying droplets and / or particles of binder or binder to mineral fibers that are entrained from a mineral fiber generating device by a carrier air stream is described in the above-cited Swedish patent application no. 8,503.805, no. Publication 452.150. It is disclosed herein that the binder or binding agent that is applied in particulate form is dosed from the same side as the mineral fibers and that the point of introduction thereof into the carrier air stream is situated before the carrier air impinges on the mineral fibers. However, the document lacks any consideration as to the possible dependence of the droplets or particles of the binder or binding agent on the carrier air stream.

U.S. Pat. No. 4,433,992 discloses a technique for spraying a binder or binder onto mineral fibers carried by a carrier air stream. According to this document, the liquid binder or binding agent composition is sprayed in the form of droplets into the fiber-carrying gas stream across the direction of flow so that the droplets have sufficient energy to penetrate the gas stream and finely disperse them due to the higher velocity. gas. With the technology described in this US document, it is believed that the high energy gas stream or carrier air stream is capable of splitting large diameter droplets into fine droplets as long as the droplets are introduced into the gas stream or carrier air stream in a transverse direction relative to its flow direction. . The data of this US document is totally inconsistent with the basic finding of the present invention that binder or binder drops have a very low tendency to split into smaller droplets or particles even when exposed to a high energy carrier air stream, resulting in inadequate use. the amount of binder or binding agent used in the manufacture of the mineral fiber web when the binder or binding agent is supplied to the carrier air stream in the form of drops.

U.S. Patent No. 5,032,334, U.S. Patent No. 5,123,949, and U.S. Patent No. 4,592,769 disclose various techniques for making mineral fiber webs. These techniques include spraying the binder or particulate binding agent onto a mineral fiber web that is retained on the conveyor. Reference is made to the aforementioned Swedish patent and to the aforementioned US patents, said US patents being incorporated herein by reference.

Depending on the specific type of fiber-forming device and the direction of the mineral fibers expelled from the mineral-fiber device, the vertical air flow may meet certain requirements in terms of transfer of mineral fibers from the mineral-fiber device to the collection point, wherein the mineral fibers are trapped to form a mineral fiber web. Thus, the carrier air stream may define a particular direction and a particular air velocity downstream of the mineral fiber generating device for driving the mineral fibers expelled from the mineral fiber generating device in the predominant direction or directions, since the particular direction of the carrier air stream may substantially coincide with the predominant direction or directions may be substantially perpendicular to the predominant direction or direction, or alternatively may define an angle with the predominant direction or directions.

Depending on the air velocity in the carrier air stream by which the mineral fibers are transferred from the mineral fiber forming apparatus to the collecting surface of the mineral fiber web, the droplets must have a diameter above a specific minimum diameter to meet the characteristic minimum diameter requirements of the invention. In a preferred embodiment of the method according to the invention, the droplets and / or particles have a diameter in the range of 10 to 300 μπ, preferably in the range of 25 to 200 μπ, in particular in the range of 50 to 150 μπ. According to the above preferred embodiment of the method according to the invention, the specific air velocity in the carrier air stream is of the order of 50 to 250 m / s.

It will be appreciated that the requirements of a specific minimum diameter conflict with certain requirements regarding maximum utilization of the binder or binding agent by further dividing the droplets and / or particles of the binder or binding agent into a plurality of smaller droplets and / or particles to increase the number of links or bonds in the binder. a mineral fiber web as compared to a mineral fiber web containing the same amount of binding agent or binder, but containing larger droplets and / or particles. Certain analysis of the conventional methods of manufacturing mineral fiber webs on which the invention is based has revealed that some compromise will be made between, on the one hand, the removal of droplets with a diameter below the critical minimum diameter characteristic of the present invention, and on the other % of the composition by further dividing the droplets and / or particles of the binder or binding agent into a plurality of smaller droplets and / or particles if the droplets and / or particles have a diameter in the range of 50 to 150 μιη. When using quite small droplets and / or particles, increased internal cohesion due to the surface tension of said droplets and / or particles over larger droplets and / or particles is used to ensure that droplets and / or particles do not inadvertently split into extremely small droplets and / or particles that could leak as described above due to the reduced tendency of smaller droplets and / or particles to fall on the mineral fibers. According to a particularly preferred embodiment of the method according to the invention, the droplets and / or particles are dispensed by the rotating droplet dispenser, since the use of the rotating droplet dispenser makes it possible to produce droplets having a substantially constant diameter and not just a diameter within a specific range. Using a spinning droplet dispenser with a specific diameter, although the number of particles differing by a specific droplet diameter produced by the spinning droplet dispenser of more than ± 10 μιη constitutes less than 1% of the total amount of droplets produced by the spinning droplet dispenser. According to a further preferred embodiment of the method according to the invention, the droplets and / or particles are produced by means of a centrifugal spinning disk producing mineral fibers. To achieve an advantageous distribution of the droplets and / or particles while mixing the droplets and / or particles with the carrier peak, it is possible to obtain an example of 70 μ ± 10 μιη, the air flow entraining the mineral fibers from the centrifugal spinning disc producing the mineral fibers. in accordance with methods known per se, preferably produced within the outer diameter of the spinning disk so that the droplets and / or particles are formed as close as possible to the formation of mineral fibers. Thus, the droplets and / or particles are preferably formed in the region of 50 to 100% of the diameter of the spinning disk, for example in the range of 80 to 100% of the diameter of the spinning disk.

To prevent droplets and / or particles being sprayed onto the mineral fibers that are ejected from the mineral fiber forming apparatus after solidification of the molten mineral material, due to the high temperature of the mineral fibers or the air in the air stream that has been heated by the mineral fibers The fibers, which do not cure, are the mineral fibers expelled from the mineral fiber generating device, preferably further cooled by said air stream, a particular air cooling stream, optionally containing water vapor or alternatively a cooling medium, or spraying water droplets onto these mineral fibers in the carrier air stream. .

The mineral fiber cooling step is preferably performed prior to the spraying step of the droplets and / or particles on the mineral fibers in the carrier air stream to avoid extremely high temperature of the mineral fibers upon droplet and / or particle impact, which could cause undesired evaporation or solidification of the droplets. or particles.

The cooling of the mineral fibers by means of water droplets can preferably be carried out in accordance with the basic principle of the invention, because according to a first preferred embodiment of the method of the invention the water droplets have a larger diameter than the minimum water droplet diameter substantially free of mineral fibers. Thus, the cooling of the mineral fibers is effected by allowing the water droplets to fall on the mineral fibers. In accordance with the above preferred embodiment of the process according to the invention, the water droplets preferably have a diameter in the range of 10 to 300 μπ, preferably in the range of 25 to 200 μπ, and in particular in the range of 50 to 150 μπ.

In accordance with an alternative preferred embodiment of the method of the invention, the water droplets have a diameter less than the minimum diameter of the water droplet substantially free of mineral fiber tendency. According to the above-mentioned alternative preferred embodiment of the method according to the invention, the mineral fibers are cooled by preventing the water droplets from falling on the mineral fibers and instead the water droplets are carried along with the carrier air stream and thereby cooling the carrier air stream with a mist droplet. cooling water. According to the above-mentioned alternative preferred embodiment of the method according to the invention, the water droplets preferably have a diameter of less than 250 µm, preferably less than 200 µm, in particular less than 150 µm, for example having a diameter in the range 10 to 250 µm, preferably in the range 20 to 150 µm. especially in the range of 30 to 100 μιη. If the water droplets sprayed onto the fibers in the carrier air stream are produced by a centrifugal spinning disk producing mineral fibers, the water droplets are produced according to known technologies within the outer diameter of the spinning disk to produce cooling water droplets as close as possible and, consequently, to cool the mineral fibers as soon as possible after they have been formed by the spinning disc. Thus, the cooling water droplets are preferably formed in the region of 50 to 100% of the diameter of the spinning disk, for example in the range of 80 to 100% of the diameter of the spinning disk.

The aforementioned objects, advantages and feature, together with a number of other objects, advantages and features, which will become apparent from the detailed description of preferred embodiments of the invention set forth below, are achieved according to a second aspect of the invention by a method of manufacturing a mineral fiber web comprising the steps of:

melting the mineral material and forming a stream of molten mineral material, guiding said stream of molten mineral material to the mineral fiber forming apparatus to form the mineral fibers by solidifying said molten material, expelling said solidified mineral fiber material in the form of mineral fibers from said mineral fiber forming apparatus, an air flow downstream of said mineral fiber generating device for entraining said mineral fibers from said mineral fiber generating device, forming and spraying droplets and / or particles of a thermosetting binder or binding agent on said mineral fibers in said carrier air stream such that said droplets and / or the particles fell on said mineral fibers, said droplets and / or particles being predominantly larger in diameter than e a minimum diameter corresponding to the droplet and / or particle substantially free of said mineral fibers in said carrier air stream, collecting said mineral fibers from said carrier air stream on the collecting surface of the mineral fiber web to form a nonwoven mineral fiber web and heating a non-woven mineral fiber web to an elevated temperature to cure droplets and / or particles of said thermosetting binder to interconnect said mineral fibers in said nonwoven mineral fiber web, thereby forming said mineral fiber web.

In accordance with a third aspect of the invention, the aforementioned objects, advantages and feature, together with a number of other objects, advantages and features, which will become apparent from the detailed description of preferred embodiments of the invention, are achieved by a mineral fiber nonwoven web comprising:

a melting apparatus for melting mineral material and forming a stream of molten mineral material, a device for producing mineral fibers, a device for guiding said stream of molten mineral material to said mineral fiber forming apparatus to form mineral fibers by solidifying said mineral material and expelling it in the form of mineral fibers said mineral fiber generating device, a device for generating and guiding a carrier air stream of a specific direction and at a specific air velocity downstream of said mineral fiber generating device for entraining said mineral fibers from said mineral fiber generating device, droplet generating and spraying device, and / or particles of a thermosetting binder or binding agent to said mineral fibers in said carrier air stream such that said droplets and / or particles impact and adhere to said mineral fibers, wherein the formed droplets are predominantly larger in diameter than a minimum diameter corresponding to a droplet substantially free of said mineral fibers in said carrier air stream, and capturing said mineral fibers entrained by said air stream to form said non-woven mineral fiber web.

The aforementioned objects, advantages and feature, together with a number of other objects, advantages and features, which will become apparent from the detailed description of preferred embodiments of the invention set forth below, are achieved by a fourth aspect of the invention by a nonwoven mineral fiber web comprising:

a melting apparatus for melting mineral material and forming a stream of molten mineral material, a device for producing mineral fibers, a device for guiding said stream of molten mineral material to said mineral fiber forming apparatus to form mineral fibers by solidifying said mineral material and expelling it in the form of mineral fibers said mineral fiber generating device, a device for generating and guiding a carrier air stream of a specific direction and at a specific air velocity downstream of said mineral fiber generating device for entraining said mineral fibers from said mineral fiber generating device, droplet generating and spraying device, and / or particles of a thermosetting binder or binding agent to said mineral fibers in said carrier air stream wherein said droplets and / or particles impinge on and adhere to said mineral fibers, the droplets formed having a predominantly larger diameter than a minimum diameter corresponding to a droplet substantially free of said mineral fibers in said carrier air stream, capturing said mineral fibers entrained by said air stream to form said non-woven mineral fiber web and an apparatus for thermally curing said droplets and / or particles of said thermosetting binder or binding agent to cure said droplets and / or particles to interconnect said mineral fibers of fibers in said non-woven mineral fiber web to form said mineral fiber web.

The aforementioned objects, advantages and feature, together with a number of other objects, advantages and features, which will become apparent from the detailed description of preferred embodiments of the invention set forth below, are achieved according to a fifth aspect of the invention by a mineral fiber product comprising mineral fibers. together connected to the integral structure only by means of a binder or hardener originally present in the uncured non-woven mineral fiber webs from which the product is manufactured, in the form of droplets with a diameter in the range 10 to 300 μιη, preferably in the range 25 to 200 μη, especially in the range 50 to 150 μιη.

The mineral fiber product according to the invention exhibits properties, expressed, for example, as mechanical characteristics or mechanical integrity, such as elasticity and strength, which constitute a substantial improvement of the mineral fiber product compared to similar conventional mineral fiber products or alternatively, if the characteristics of the mineral fiber product fibers of the invention identical to that of a similar conventional mineral fiber product, expressed, for example, in accordance with the above characteristics, wherein the product of the invention contains a radically reduced amount of cured binder or binder, resulting in a more favorable product price compared to conventional product flame resistance of the product compared to a conventional product.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described in more detail with reference to the accompanying drawings, in which:

Fig. 1 schematically shows an apparatus according to the invention for producing a non-woven mineral fiber insulating web.

Fig. 2 schematically shows part of the device also shown in FIG. 1, representing a specific production point of 18 meters.

Fig. 3 is a schematic partial cross-sectional view of the spinning disk shown in FIG. 1 and 2.

Fig. 4 is a schematic cross-sectional view of the peripheral segment of the spinning disk shown in FIG. Third

Fig. 5 to 7 are reproductions of photographs illustrating the formation of droplets of binder or binding means by the spinning disk shown in FIG. Third

Fig. 8 and 9 are perspective views showing alternative embodiments of the apparatus of the invention for producing a non-woven mineral fiber web.

Fig. 10 graphically illustrates the tendency of a droplet of a particular diameter to impact an object when exposed to a particular carrier air stream.

In FIG. 1 shows a first embodiment of an apparatus for carrying out the method of the invention for producing a non-woven mineral fiber web. The apparatus centrally comprises a rotating spinning disk 10 rotating at a high rotation speed, such as 5 to 15,000 min, about a substantially horizontal output shaft 12 of the speed generating motor 14. The spinning disk 10 defines an outer cylindrical surface 16 that is used to produce mineral fibers from a stream of molten mineral material that is ejected from the outlet 18 as a stream 20 of molten mineral material. The spinning disk 10 rotates in the direction shown by the arrow 15. The spinning disk 10 is, as described in more detail below, cooled to a temperature below the melting point of the mineral material in the molten stream 20 and thereby causes the molten material to solidify upon contact with the outer cylindrical surface 16. 10th

As the mineral material solidifies in the stream 20, mineral fibers are formed which are forced to move from the spinning disk 10 toward the mineral fiber collector 22 formed by a perforated conveyor belt 24 that is guided around two rollers 26 or 28 in the direction indicated by the arrow 25. formed by the spinning disk 10 are carried by the carrier air stream generated by the air outlets 32 and 34 moving in the direction of the arrows 35 and collected in the mineral fiber stream 30. The carrier air stream outlets 32 and 34 are preferably located circumferentially around the spinning disk 10, because more than two carrier air stream outlets, for example 4 to 6 or more, are preferably located. The spinning disk 10 serves, in addition to solidifying the molten mineral material from stream 20, to form mineral fibers in the stream 30, two other purposes, namely, the purpose of forming and spraying droplets of binder or mineral fiber binder in the mineral fiber stream and spraying water droplets onto the mineral fiber stream to induce mineral fiber cooling. The droplets of the binder or binding means are formed by the jagged face 40 of the spinning disk 10, which comprises a toothed inner rim 42 constituting an essential element of droplet forming of the binder or binding means. The droplets of binder or binder are sprayed with 44 droplets.

The cooling of the mineral fibers in the stream 30 is effected by the water droplets forming the spraying 46. The water droplet spraying 46 is formed of water pumped into the interior of the rotating spinneret 10 to cool the outer cylindrical surface 16 of the spinneret 10. a plurality of apertures 48 disposed in the surface portion of the cylindrical surface 16 of the spinning disk 10, the surface portion adjacent to the toothed inner rim 42 of the face 40 forming droplets of binder or binding means.

Spray 46 serves essentially the purpose of cooling the mineral fibers to a temperature below the curing temperature of the binder or binder in the spray 44 so as not to cure the droplets of the binder or binder in the spray 44 upon contact with the mineral fibers in the stream 30 without forming. bonding to adjacent mineral fibers upon entrapment of mineral fibers on the conveyor 22 in the form of a nonwoven web 50.

In addition to forming binder droplets or binding agent droplets by the face 40 of the spinning disc 10, two or more directionally adjustable nozzles 52 are formed to form binder droplets or binding agent droplets 54 that form a spray of binder droplets or binding agent droplets. Spray droplets 44 and 54 and preferably also cooling water spray droplets 46 have specific characteristics according to the invention as regards their minimum and maximum diameters. Alternatively, the droplets of cooling water spray 46 may have a characteristic as to the maximum diameter that the droplets produce a cooling effect by creating a mist of droplets.

In FIG. 2 shows a larger scale segment of the device according to FIG. 1. Spray 44 is shown in FIG. 2 is shown in more detail with two dashed boundary curves 60 and 62, the meaning of which is described below. Further, FIG. 2 shows three dotted lines 64, 66 and 68 that divide the mineral fiber stream 30 into two parts A and B.

The dashed line 60 represents a curve along which a binder or binder droplet moves when the bead has a diameter less than the minimum binder or binder droplet diameter substantially free of the tendency to impact the mineral fibers at the air velocity in the carrier air stream formed in the airflow. When the droplet has a smaller diameter than the minimum diameter mentioned above, it does not show a substantial tendency to impact the mineral fibers in the stream 30 because it is merely entrained by the carrier air stream. The dashed line 62 represents a curve along which a droplet of binder or binding agent moves, when the droplet has an extremely large diameter, causing the droplet to flow through a stream of 30 mineral fibers due to its extremely large diameter and further to its large mass and inertia. , without falling on any mineral fiber.

Thus, curves 60 and 62 represent boundary lines corresponding to the specific droplet diameter range within which the binder or binder droplets formed by the spinning disc 10 are to be moved. Preferably binder or binder droplets with a diameter smaller than the droplet corresponding to the curve should not be formed. 60, and having a diameter greater than the droplet corresponding to curve 62, since such droplets are very likely to escape, as they will only be entrained by the carrier air stream, respectively. overflows due to the high inertia of the stream 30 without impacting the mineral fibers.

Like the binder or binding agent droplets, the cooling water spray droplets 46 preferably have a larger diameter than the minimum water droplet diameter, substantially free of mineral fibers at the carrier air flow rate, to achieve maximum cooling efficiency of the droplets of cooling water. Alternatively, the cooling water droplets may form an aqueous mist that cools the carrier air stream and surrounds the mineral fibers in the stream 30 as long as the cooling water droplets have a diameter less than the minimum diameter mentioned above.

Sections A and B, defined by dashed lines 64, 66 and 68. preferably, they form separate regions of the mineral fiber stream 30 in which the mineral fibers or the mineral fibers are cooled, respectively. incident droplets of binder or binder on the mineral fibers in the stream 30.

In FIG. 3, the spinning disk 10 is shown in more detail, showing some of its components. As shown in FIG. 3, the output shaft 12 is formed by a hollow shaft through which two tubes 70 and 72 pass through, the purpose of which is to supply cooling water, respectively. a binder or binding agent. The cooling water supplied by the tube 70 is ejected into the interior of the cylinder drum 74 defining the outer cylindrical surface 16 of the spinning disc 10. The cylinder drum 74 includes internal guide flaps, in FIG. 3 (not shown) for guiding the cooling water supplied by the tube 70 to the inner cylindrical surface of the cylindrical drum opposite the outer cylindrical surface 16 and for discharging the cooling water in the form of cooling water droplets from the apertures 48. wherein, under the action of centrifugal force, it impinges on the rim of the outer ring gear 42 and is ejected in the form of droplets of binder or binding means with a specific diameter range.

In FIG. 4 shows a segment of the inner surface of the ring gear 42 of the spinning disk face 40, comprising radially extending tooth surfaces 76, which on one side communicate with a radially projecting surface 78, along which a binder or a binder in the form of a liquid film is supplied from the metering slot. and, on the other hand, communicate with the jagged edges 82, which cause the binder film or binding agent to distribute into droplets with a specific diameter range.

Fig. 5, 6 and 7 are photo reproductions of a spinning disk similar to the spinning disk 10 described above with respect to FIG. 1-4, rotating at high speed in the order of 8-15000 min ^- * · · having a toothed droplets generating rim part similar to the rim part 42 of FIG. 1 to 4, to form droplets of a binder or binding agent, which are first formed as a flow of liquid, which then disintegrates into individual droplets. Surprisingly, it has been found that the aforementioned toothed rim 42 of the spinning disk 10 makes it possible to determine very precisely the diameter of the droplets of binder or binding means formed. The basic technology of droplet formation with a specific diameter by means of a rotating ring gear is described in the above-cited patent documents referred to herein and whose US analogs are hereby incorporated herein by reference.

In FIG. 8 and 9, two alternative apparatuses for producing a nonwoven mineral fiber web according to the invention are shown. In FIG. 8 is a device having a substantially similar construction to that described in U.S. Pat. No. 5,123,949, which is incorporated herein by reference, includes a spinning disk 110 which is mounted on a vertical shaft 112. A mineral fiber stream 130 is ejected from the disk-shaped dispenser 113. In advancing to the collecting surface 122, the mineral fiber stream 130 may be driven by a carrier air stream. The spinning disk 110 includes two further sections 116 and 140 for spraying 146 droplets of cooling water and water, respectively. spraying 144 droplets of binder or binding agent. The section 140 has a gear ring 142 similar to the gear ring 42 described with reference to FIG. The binder or binder spray droplets 144 and the cooling water spray droplets 146 have diameters within the relevant diameter ranges determined in accordance with the invention so that the binder or binder droplets hit the mineral fibers in the stream 130 and the cooling water droplets fall on the mineral fibers in the stream 130 or alternatively to prevent droplets of cooling water from falling on the mineral fibers in the stream 130 and instead create a water mist surrounding the mineral fibers in the mineral fiber stream. In addition to spraying binder droplets or binding agent droplets 144, a binder or binding agent dispenser or directionally adjustable nozzle 152, similar to nozzle 52 described above with reference to FIG. 1 and 2, for spraying 154 droplets of a binder or binding agent of the invention in the manner described above with reference to FIGS. First

In FIG. 9 shows another apparatus for producing a nonwoven mineral fiber web according to the invention. The apparatus includes a reservoir 160 in which molten mineral material 162. is contained. A mineral fiber stream 166 is extruded from the molten mineral material dispensing nozzles 164. The mineral fiber stream 166 travels to a collection conveyor 172 similar to the collection surface 122 described above with reference to FIG. 8, and is driven by a carrier air stream that carries the mineral fibers towards the collecting conveyor 172. The mineral fiber stream 166 is cooled by spraying or cooling water mist generated by the nozzles 168. The spraying or mist comprises droplets of cooling water preferably having a diameter greater than higher. said diameter of the water droplet carried by the air at a specific velocity of the carrier air stream. By means of the binder or binding agent dosing nozzles 152, a spray of binder droplets or binding agent droplets 154 is sprayed onto the mineral fibers in stream 166 so that the droplets of binder or binding agent fall on the mineral fibers in stream 166 carried by the carrier air stream. Using the collecting conveyor 172, the non-woven mineral fiber web 174 is captured and conveyed from the apparatus in the direction indicated by the arrow 175 for further processing such as folding, compression, compaction, cutting, curing, etc., similar to the mineral fiber web 50 Fig. The carrier air stream passes through the collecting conveyor 172 in the direction of the arrows 177.

In FIG. 10 is a diagram illustrating the characteristic property of droplets of a particular material, such as a water droplet or a droplet of binder or binding agent, settling vertically in a gravitational field in the atmosphere, moving horizontally at a particular velocity. The abscissa axis shows the distance in any units, such as cm or m, marked with the symbol L. The ordinate axis shows the vertical height. A total of six curves, representing a droplet path having a diameter, are shown by a circular symbol on the respective curve. Thus, curve C is a very small droplet, for example a small droplet of binder or binding agent, which is expelled from the binder or binding agent dispenser. This droplet, like the other droplets shown by curves D to H, is exposed to the carrier air stream and passes only a small distance before it evaporates or solidifies due to heat from adjacent mineral fibers. Curve D represents a slightly larger droplet that goes a little longer before evaporating or solidifying. Curves E and F are droplets that are capable of reaching the carrier air flow beyond the distance at which the droplet associated with curve C evaporates or solidifies without evaporating or solidifying. The droplets associated with curves F, G and H have sufficient inertia to contact the ground, while the droplet associated with curve E does not reach the ground within the range of distances shown on the axis of the lines.

The curves C to H shown in FIG. 10 thus represent the likelihood that a droplet and / or particle of any particular diameter will pass a specific distance in the carrier air stream before it evaporates or solidifies and reaches the ground. Based on similar sets of curves representing droplets of specific diameters, exposed to a specific carrier air velocity, it is possible to calculate or determine a relevant range of droplet diameters and / or particles having both sufficient mass and inertia to prevent evaporation or solidification of the droplet. and / or the particles carry, or merely carry, the carrier air stream, and secondly have a mass smaller than that of the particle that alone travels with a reduced probability of impacting the mineral fiber carried by the carrier air stream.

DETAILED DESCRIPTION OF THE INVENTION

The spinning disk with the structure shown in FIG. 3 and having an outer diameter of 332 mm was used in a manufacturing plant for the production of a non-woven mineral fiber web, which was finally used for the production of thermal insulation boards. The spinning roll 10 was used as a substitute for the conventional spinning roll used by the applicant, and the amount of binder or curing agent used to produce the non-woven mineral fiber web was adjusted so that the amount of binder or curing agent was reduced but still obtained mineral fiber boards, not showing inferior mechanical properties compared to conventional mineral fiber boards produced using a conventional spinning disc.

Table 1

GLT density SRL σ ^and norm % kg / m ³ kg / m ³ kN / m ² kN / m ² conventional thermal insulation board 2.57 34.1 31.1 12.1 9.1 heat insulating plate according to the invention experiment 1 experiment 2 2.36 (-8%) 2.00 (-22%) 32.2 (-6%) 33.5 (-2%) 33.3 31.6 12.3 (+ 2%) 12.5 (+ 3%) 10.9 (+ 20%) 10,0 (+ 10%)

notes:

GLT represents the solidified binder content, expressed as a percentage by weight of the total mineral fiber product.

Density is the density of the mineral fiber board. SRL (air resistance density standard) is an industry standard value representing the air permeability coefficient of a thermal insulation product. The rate of SRL is preferably equal to or higher than the density of the product or board.

σ is the tensile strength of the product or board.

^CT norm ^fe normalized tensile strength, i.e. the tensile strength converted to a measure representing the tensile strength of comparable products, i.e., the tensile strength of a given product or board is converted to a normalized measure representing the tensile strength of a product containing 2.4% GLT.

The overall results of both experiments were very promising because, according to Experiment 1, a 8% reduction in binder content resulted in an improved insulation product (an increase in SRL compared to a conventional board) and a radically increased tensile strength (+ 20% compared to a conventional product). Experiment 2 resulted in a radical decrease in binder content (22% compared to the conventional product) to a product with essentially the same SRL value as the conventional product (31.6 for the plate of Experiment 2 versus 31.1 for the conventional product) and an increase tensile strength over conventional product (tensile strength increased by 10% compared to conventional product).

Although the invention has been described above with reference to particular and presently preferred embodiments of the method and apparatus for producing a non-woven mineral fiber web, numerous modifications and variations will be apparent to those of ordinary skill in the art. These modifications and variations are intended to be part of the invention as defined in the appended claims. It is further contemplated that more accurate and accurate dosing of droplets and / or particles of binder or binding agent within a preselected diameter range can improve the characteristics of products made from the nonwoven mineral web of the present invention, since it is possible to reduce the binder or curing agent content. having adequate mechanical properties compared to similar conventional products, or alternatively, products with better mechanical properties compared to similar conventional products having the same binder or binding agent content can be obtained.

Claims (20)

PATENT CLAIMS A process for producing a non-woven mineral fiber web, comprising the steps of: melting the mineral material and forming a stream of molten mineral material, guiding said stream of molten mineral material to the mineral fiber forming apparatus to form the mineral fibers by solidifying said molten material, expelling said solidified mineral fiber material in the form of mineral fibers from said mineral fiber forming apparatus, an air stream downstream of said mineral fiber generating device for entraining said mineral fibers from said mineral fiber generating device, forming and spraying droplets and / or binder particles or binding agent on said mineral fibers in said carrier air stream, said droplets and / or the particles have a predominantly larger diameter than the minimum diameter corresponding to the droplet and / or the particles substantially not showing a tendency to impact said mineral fibers in said carrier air stream such that said droplets and / or particles, predominantly having a diameter greater than said minimum diameter, impinge on and adhere to said mineral fibers and collecting said mineral fibers from said carrier air stream on the collecting surface a mineral fiber web to form said nonwoven mineral fiber web. Method according to claim 1, characterized in that said droplets and / or particles of said binder or binding agent have a diameter in the range of diameters whose lower limit is equal to or greater than said minimum diameter. Method according to any one of claims 1 or 2, characterized in that said droplets and / or particles of said binder or binding agent have a diameter in the range of diameters, the mean value of these diameters being slightly greater than said minimum diameter, and more than 75 up to 95%, for example 80 to 95%, in particular 90% of these droplets and / or particles have a diameter greater than said minimum diameter. Method according to any one of claims 1 to 3, characterized in that said minimum diameter is of the order of 10 to 75 μιη, for example 25 to 50 μιη. A method according to claim 1, characterized in that said mineral fibers are formed by means of a spinning disk, a centrifugal spinning device, a nozzle for extruding said mineral fibers or a similar mineral fiber generating device. Method according to any one of claims 1 to 5, characterized in that said carrier air stream defines a specific direction and a specific air velocity downstream of said mineral fiber generating device for entraining said mineral fibers expelled from said mineral fiber generating device. a predominant direction or directions, said specific direction of said carrier air stream being substantially coincident with said predominant direction or directions, substantially perpendicular to said predominant direction or directions, or alternatively defines an angle with said predominant direction or directions. A method according to any one of claims 1 to 6, characterized in that said droplets and / or particles have a diameter in the range of 10 to 300 μιη, preferably in the range of 25 to 200 μιη, in particular in the range of 50 to 150 μπι. Method according to any one of claims 1 to 7, characterized in that said specific air velocity in said carrier air stream is of the order of 50 to 250 m / s. A method according to any one of claims 1 to 8, characterized in that said droplets and / or particles are dispensed from a rotating drop dispenser. The method of any one of claims 1 to 9, further comprising the step of cooling said mineral fibers expelled from said mineral fiber generating device by said air stream, a separate air stream, optionally containing water vapor or alternatively a cooling medium, or spraying water droplets onto said mineral fibers in said carrier air stream. The method of claim 10, wherein said step of cooling the mineral fibers is performed prior to spraying said droplets and / or particles onto said mineral fibers in said carrier air stream. A method according to any one of claims 10 or 11, characterized in that said water droplets have a diameter greater than a minimum diameter of a water droplet substantially free of the tendency to impact said mineral fibers. Method according to claim 12, characterized in that said water droplets have a diameter in the range of 10 to 300 µm, preferably in the range of 25 to 200 µm, in particular in the range of 50 to 150 µm. A method according to any one of claims 10 or 11, characterized in that said water droplets have a diameter less than the minimum diameter of a water droplet substantially free of the tendency to impact said mineral fibers. Method according to claim 14, characterized in that said water droplets have a diameter of less than 250 μιη, preferably less than 200 μιη, in particular less than 150 μπη, for example having a diameter in the range 10 to 250 μιη, preferably in the range 20 to 150 μιη, in particular in the range 30 to 100 μιη. The method according to any one of claims 1 to 15, characterized in that said binder or binding agent is heat curable, further comprising heating said non-woven mineral fiber web to an elevated temperature to cure droplets and / or particles of said heat curable binders for interconnecting said mineral fibers in said non-woven mineral fiber web, thereby forming said mineral fiber web. 17. An apparatus for producing a non-woven mineral fiber web, comprising: a melting apparatus for melting mineral material and forming a stream of molten mineral material, a device for producing mineral fibers, a device for guiding said stream of molten mineral material to said mineral fiber forming apparatus to form mineral fibers by solidifying said mineral material and expelling it in the form of mineral fibers said mineral fiber generating device, a device for generating and guiding a carrier air stream of a specific direction and at a specific air velocity downstream of said mineral fiber generating device for entraining said mineral fibers from said mineral fiber generating device, droplet generating and spraying device, and / or particles of a thermosetting binder or binding agent for said mineral fibers in said carrier air stream, wherein said formed droplets and / or particles are predominantly larger in diameter than a minimum diameter corresponding to a droplet substantially free of said tendency to impact said mineral fibers in said carrier air stream, such that said droplets and / or particles predominantly have a diameter greater than said minimum and an apparatus for collecting said mineral fibers carried by said air stream to form said non-woven mineral fiber web. The apparatus of claim 17, further comprising any of the characteristics of the method of any one of claims 1 to 16. 19. A mineral fiber product comprising mineral fibers, characterized in that said mineral fibers are interconnected into an integral structure only by means of a binder or hardener originally present in the uncured non-woven mineral fiber webs from which said product is produced in the form of droplets. with a diameter in the range 10 to 300 μιη, preferably in the range 25 to 200 μιη, in particular in the range 50 to 150 μιη. A mineral fiber product according to claim 19, characterized in that it is further obtained by a process according to any one of claims 1 to 16 or by using a device according to any one of claims 17 to 18.