FI97164B - Formed product based on mineral wool and its manufacturing process - Google Patents

Description

97164

The invention relates to a mineral wool-based molded article prepared in particular by a vacuum molding process in which solid particles are added to a suspension containing a liquid and a binder in which the mineral wool has been decomposed, after which solid particles have been added. from the suspension to the mineral fibers, and wherein the mineral fibers are bonded to each other by said binder contained in the suspension. The invention further relates to a method for producing such a molded body.

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Molded articles based on mineral wool, which are used in particular as cover plates or sheaths around pipes, are generally made by dispersing mineral wool in a binder suspension, after which the mineral wool 20 thus obtained is drained and dried in a casting substrate or mold under vacuum. Diatomaceous earth and starch are known to be used as binders. The mineral wool can be, for example, rock wool, glass wool, aluminosilicate wool or a mixture of these products.

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In addition, the mineral wool can be completely dyed by this method by adding a dye to the binder suspension. In order to make the molded body colored black, a suitable black-colored substance, for example activated carbon, carbon black or printing ink, is added to this suspension.

In order to form a suitable layer of solid particles on the fibers and in this way to provide a uniform bond with the binder and / or to uniform the color of the final product, diatomaceous earth, starch and colored pigment must be added to the water in sufficient amounts. In practical applications, 97164 2 excess binder is always used, which is present in a considerable amount in the water separated by suction. This excess of binder in the suspension leads to the formation of colloids as well as to the thickening of the dispersion, which is not advantageous in terms of good layering and even distribution in the wool. In addition to this first problem, the residual concentration of binder causes the suspension to be contaminated with microorganisms during each prolonged downtime, for example a weekend, which is why the suspension must be renewed every time. If dyes are used for li-10, the staining particles must be separated by filtration from the effluent before discharge to the sewer. Excess binders and pigments cause not only an increase in raw material costs but also costs in post-treatment and treatment of wastewater. In addition, it can be seen from the final product, especially if it is dyed in its entirety, that the mineral fibers are overloaded with solid particles, which in turn causes the desired properties to be impaired.

The known mineral fiber-based products according to the above, in which solid particles have been added to the fibers bound together by a binder in suspension, and the production methods of the products are described in FI patent applications 1666/65 and 772044, FI-A-25 62526, DE-A-29 34 677 and -: in section 4 668 590.

The object of the invention is to provide a molded body based on mineral wool which has special properties due to the permanent and uniform deposition of solid particles 30 and good distribution of the binder and which can be obtained by using the various components sparingly. 1

The molded article according to the invention is characterized in that the average particle size of the solid particles is 4 μιη or less and that the particles are deposited on the mineral fibers as islands with the aid of a substance which increases the electrical conductivity of the liquid phase of the suspension.

These molded articles are preferably made by vacuum-5 molding.

According to a first aspect of the invention, it is an object to provide a shaped body based on mineral wool, in which solid particles are deposited as islands between mineral fibers impregnated with a binder, preferably using a suspension in water. Surprisingly, it has been found that such islanding makes it possible to adjust the properties of a body over a wide area. For example, the molded article can be dyed black with additional particles deposited as islands on the mineral fibers, this layer of discrete islets surprisingly being sufficient to achieve complete discoloration of the mineral wool so that complete dye coating of the mineral fibers is not necessary. The same is true for adjusting other properties such as radiation absorption.

Thus, various properties can be achieved in a very simple manner by forming layers over the entire thickness of the molded article. For example, clay deposition can provide molded articles that can withstand very high temperatures and can be used to coat water vapor lines. Water or gas filters can be formed by depositing activated carbon. By depositing acids, bases, metals or their oxides, catalysts can be obtained whose properties can be adjusted very precisely. Microwave and especially radar absorbing materials can be obtained by depositing carbon black or graphite, and such materials can be used especially in areas near airports to avoid false signals from waves reflected from buildings.

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Manufacturing costs have been significantly reduced by using smaller amounts of binder and solid particles. Furthermore, the mineral fibers are not overloaded by using too large amounts of binder and layerable solid particles, thus avoiding the presence of irregularly pleated areas in the mineral wool due to the overloading of the mineral wool. The method can be used to obtain a molded body with very uniform properties. Particles with a diameter of less than 4 μπι 10 are significantly deposited as islands between the mineral fibers. The average diameter of the particles is preferably 1 to 4 μπι, more preferably 1 to 3 μπι, but satisfactory results are also obtained with even smaller particles, and in particular particulate dyes at the molecular level can be used.

When depositing solid particles, organic and inorganic substances can be used as a transport medium, in which suspension the binder is made to disperse. These carriers also act as a binder, so the addition of a binder is not necessary. These organic and inorganic substances are preferably cationic and / or anionic.

According to one example related to the practice of the invention, the organic material consists of tylose and / or starch and the inorganic material consists of diatomaceous earth. A mixture of tylose, diatomaceous earth and / or starch can act as a binder. By using tylosis, the amount of starch can be reduced to 10 to 30 parts, whereby the products obtained belong to flammability class A1.

The mechanical strength of the part can be improved by layering thermoplastics or thermosets. Using silicones, hydrophobic bodies are obtained which can be placed in a humid atmosphere. Graphite particles improve the conductivity of the part. Using aluminum hydroxide or other substances rich in water of crystallisation, refractory

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5 97164 molded pieces, for example plates for fire doors. In all these cases, the discontinuous layers are sufficient to provide the desired properties.

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As mineral wool, stone wool is particularly preferably used. Due to the fact that the solid particles are organized into several layers, the amount of particles contained in the molded body can be reduced. For example, the clay particles can be layered into a first layer and the dye particles into a second layer. If desired, more than two layers can be implemented.

The method according to the invention for producing a shaped body based on mineral wool, in which the mineral wool is dispersed in a suspension containing liquid and binder and the body is formed by bonding mineral fibers together with a binder, is characterized by adding solid particles with a smaller average size of , and that the electrical conductivity of the liquid phase of the suspension is adjusted by means of a conductivity-increasing agent to at least 700 μβ / οιη, preferably 800 μδ / οτα, said solid particles precipitating from the suspension on the mineral fibers into separate layered rusted islands.

As mentioned above, the suspension of solid particles is preferably formed with water having a conductivity of at least 700 μβ / cm, preferably at least 800 μβ / αη. By adjusting the conductivity of the water, excellent deposition of the binder and other solid particles on the mineral wool is achieved so that excesses of diatomaceous earth, starch and any tylosis and other possible solid particles are not necessary. In contrast, if a high conductivity value is maintained in the preparation, all the components in the suspension will migrate and deposit in the mineral fibers, and virtually no residues of these substances will remain in the water. As a result, material costs, as well as manufacturing costs, are reduced, in particular because cleaning operations are no longer required.

In a particularly preferred embodiment, the water conductivity is set in the range of 900 to 1000 μ3 / οπι. Such conductivity is obtained, for example, by the addition of conductive substances, such as metal salts, in particular magnesium sulphate.

Preferably, solid particles with an average diameter of less than or equal to 4 μια are added to the suspension. Particularly suitable are solid particles formed from carbon, clays, dyes, thermoplastics, thermoplastics, acids, bases, metals, metal oxides, silicones, water-rich substances and / or the like. Mixing further increases the deposition rate as various components are added.

Multi-layer deposition of solid particles is particularly advantageous if the solid particles to be deposited in the first step are mixed directly with an aqueous suspension of a carrier, in particular tylose and / or starch and diatomaceous earth, after which mineral wool is added so that all binder and all solid particles adhere to the islands. leaving no residue of these substances in the water. In the second step, diatomaceous earth and tylose and / or starch as well as other depositable solids can be re-added to the water, whereby the binder and these other solid particles are deposited between the already loaded mineral fibers. If necessary, other additional measures may be taken. 1 it The quantitative dosing of these various components can be carried out very simply by adding to the dispersion so much tylosin and / or starch that all the solid particles are deposited between the mineral fibers.

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In a practical embodiment, the dispersible mineral wool is added to the water in a container having a volume of about 5,500 liters. With constant stirring of the contents of the vessel, the other components of the suspension, i.e. diatomaceous earth, tylose and / or starch and the solid particles to be layered, are added. For black dyeing, activated carbon or carbon black is preferably added to the vessel simultaneously with the tylose. In this way, the pigment particles travel simultaneously with the binder to the surface of the fibers and the layer-10 enters it. It should be noted that the deposition takes place into islands, which are seen in the microscope as discrete points evenly distributed between the mineral fibers.

If the aim is to improve the thermal stability 15 of the molded body, clay must be added to it, in which case the clay particles travel simultaneously with the binder to the surface of the fibers.

Further, flocculation of the fibers is improved if clay 20 is added together with potato starch.

As cellulose, methylcellulose is preferably used. Starch can also be used instead of tylose. It is also possible to add both tylose and starch. It is essential that the conductivity of the water be set to a value of at least 700 [mu] S / cm, preferably at least 800 [mu] S / cm. In particular, metal salts such as magnesium sulfate can be used as water conductivity additives. When the conductivity of the water is suitable, the deposition on the surface of the mineral fibers 30 takes place after the addition of silicon and tylose or starch so that excesses of these components are not necessary. The additional solid particles, which are intended to impart predetermined properties to the molded body, such as temperature resistance or the like, travel simultaneously with the binder to the surface of the mineral fibers, so that, like the binder, these solid additives do not have to be used in excess. After the components used have coalesced on the surface of the mineral fibers, the residual water is completely pure and can be decommissioned as such, after being filtered to recover the mineral wool particles still present therein. This water can likewise be used directly again, in particular to deposit several layers, by adding the components which are absent from the binder effect before each step, i.e. diatomaceous earth and tylosin and / or starch, together with solid particles still to be deposited, for example clay or dye particles.

To date, only the deposition of clay and / or dye particles has been described, although other suitable solid particles may be deposited on the surface of the mineral wool or mineral fibers. For example, in order to improve the absorption of radiation or to increase the slipperiness, graphite can be deposited on the body, for which purpose the graphite particles are added to the suspension in which the mineral wool is to be dispersed.

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The average particle size of the solid particles to be added is preferably less than or equal to 4 μηι, more preferably 1-3 μm. When depositing dyes, particles with a size in the molecular range can be added.

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In the case of a more heat-resistant molded article, the following composition can typically be used: 98.939% 1 ^ 0 0.0989% MgSO 4 0.0074% tylose 0.5194% mineral wool 0.0890% clay 0.3463% diatomaceous earth. 1

In the case of a black colored molded article, the following composition can typically be used: 97164 9 99,000% H 2 O 0.0742% MgSO 4 0.0396% starch 0.5399% mineral wool 0.3467% diatomaceous earth 0.00248% Fakunyl black.

In the case of a microwave absorbing article, for example, the following suspension composition is suitable: 98.76% H 2 O 0.09876% MgSO 4 0.37037% 10% suspension of carbon black 0.00493% tylose 0.02469% anionic diatomaceous earth (40%) 34566% cationic diatomaceous earth (30%) 0.54318% mineral wool.

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Claims (12)

1. A mineral wool base mold part, made in particular by a vacuum process in which, in a suspension of a liquid and a binder in which the mineral wool has dissolved, solid particles have been added to control the properties of the mold part to be made. which has subsequently been precipitated from the suspension of the mineral fibers, and in which the mineral fibers have been bonded together by the binder contained in the suspension to form said mold, characterized in that the solid particles have an average particle size of 4 µπι or less and the particles are arranged in the form of islands of the mineral fibers using a conductivity of the suspension liquid raising agent. 15 2. A molding part according to claim 1, characterized in that organic and inorganic substances have been used as transport means for the deposition of the solid particles. The molding part according to claim 2, characterized in that the organic and inorganic substances are of anionic and / or cationic nature. 4. A molding part according to any of the preceding claims, characterized in that said inorganic substance consists of silica sol and said organic substance consists of tylosis and / or starch. 5. A molding part according to any of the preceding claims, characterized in that the solid particles are formed of carbon, clay, dye, thermoplastic, thermosetting resin, acid, base, metal, metal oxide, silicone and / or a high crystal water content substance. . 6. Mold part according to any of the preceding claims, characterized in that carbon particles or graphite have been used as solid particles and that the mold part is radar path absorbent. II 97 ^ 64 7. A molding part according to any of the preceding claims, characterized in that the solid particles have been deposited in several layers. 5 8. A process for making a mineral wool base mold in which the mineral wool is dispersed in a suspension of a liquid and a binder and the mold portion is formed by bonding the mineral fibers with each other, characterized in that solid particles 10 are added with the suspension. an average particle size of 4 µm or less and that the conductivity of the liquid phase of the suspension is controlled by a conductivity raising agent of at least 700 µS / cm, preferably 800 µβ / αη, the solid particles being precipitated from the suspension on the mineral fibers insulated. . Method according to claim 8, characterized in that water is used as the conductive medium. 20 Method according to Claim 8 or 9, characterized in that in order to deposit the solid particles in several layers on the mineral fibers, a carrier and solid particles are added in several successive steps in the suspension. 25 11. A method according to any of claims 8-10, characterized in that in the suspension, transport means are added sufficiently to deposit all the solid particles between the mineral fibers. 1 Process according to any one of claims 9-11, characterized in that metal salts, especially magnesium sulfate, are added in water to increase its conductivity.