Insulating fibrous material and method of its manufacture

 

(57) Abstract:

Use: for the production of heat and sound insulation materials used in construction. The inventive monolithic material contains interwoven fibers, binder and surfactant. The density of the material is generally in 5 to 20 times. The material is prepared as follows. Prepare foamed fibrous aqueous suspension of the fiber binder and a surfactant to produce a molding material from a suspension containing 60 to 90% air. At the same time carry out dehydration for at least 5 min, better 5 25 min under the action of gravitational forces. The dehydrated material is dried. 2 S. p. f-crystals, 1 table.

The invention relates to the production of fibrous material having good heat and sound insulation properties and is intended for use in construction, shipbuilding, aerospace, industrial and furniture industry and other sectors of the economy.

Known insulating material weights up to 100-200 kg/m3made of glass fiber by spraying a binder formed on canvas [1]

Fiberglass, alwaysthe, has limited use because of its toxicity (irritating to skin) and lack of strength.

Known insulating material having high strength characteristics and represents a glass fiber, coated on both sides with the plates [2]

However, the material coated on one or both sides of the facing sheets (paper, non-woven material), not only strengthened, but also becomes more difficult, due to a high density of facing sheets. In addition, the traditional manufacturing technology of glass virtually eliminates the possibility of introducing in its composition some chemical additives capable of imparting the glass fiber specific properties, as they (additives) are badly kept in the material produced by the dry method.

The closest analogue of the present invention is a material consisting of a porous core, formed from a foamed fibrous suspension containing bound mineral and chemical fibers, particles of expanded perlite, binder and surfactant, and at least one coating layer. The covering layer is made of a thin porous material, e.g. the material as a whole. Performing material with uneven density across the thickness, namely, when the surface layers (layer) has a higher density than the core or material in General, provide him (material) necessary strength and structural properties, such as the frame.

The method of manufacture of this material is as follows.

Prepare foamed fibrous aqueous suspension containing in addition to the mineral fiber particles of expanded perlite, starch, cationic guar gum, surfactant and dispersing funds. Then saturate it with air to the content in the formed foam 10-30%

After that molded porous core of foamed fibrous slurry on a porous fabric, which is fed to the grid of the paper machine and moves together with it. Porous cloth (paper, non-woven fabric) to form a facing layer to a porous core formed from intertwined fibers. Simultaneously with the molding are dehydrated porous core in the process of its formation by exposure to vacuum and subsequent drying of the molded core in a stream of hot air, if necessary, to t the th 50-160 kg/m3, thickness 0,6-5,0 see Material coated on one or both sides of the plates, the density of which is of the order of 400-700 kg/m3the thickness of 30-60 μm.

The disadvantage of this material is its relatively high density. This is explained, first, by the presence of surface layers (layer) made of a material more dense than the core material that the weight of the material as a whole, and, secondly, intense dehydration (under vacuum) of the core during its formation, which contributes to the rapid destruction of the bubbles of the foam, resulting in compaction of the fibers to each other. In addition, the cladding layers can flake off from the core, as the connection between them is purely mechanical and is formed only at the expense of the adhesion forces arising in the process of dehydration of the material during the molding of the core and directly dependent on the magnitude of the vacuum.

The method of manufacture of this material is quite energy intensive and technically difficult to implement, as it provides for the mandatory use of lining cloth, lying on a grid paper machine and moving along with it.

The present invention consists in the co - and sound insulation characteristics, free from the disadvantages inherent in the prototype.

The problem is solved due to the fact that, in accordance with the invention, the insulating fibrous material with a porous structure made of monolithic, i.e., in contrast to the prototype it is not formed by two or three separate structures connected to each other, and represents a homogeneous composition stratifying the porous material of the intertwined fiber density up to 10-50 kg/m3. The density of the material near the surface 5-20 times greater than the density of the material as a whole.

This material provides good structural properties at a very low overall density. Fabrication of monolithic material completely eliminates it unmixing.

The object of the present invention is also a method of manufacturing a monolithic porous fibrous material density up to 10-50 kg/m3with the density at the surface is 5 to 20 times higher than the density of the material as a whole.

The proposed method involves preparation of an aqueous suspension of fibers, binders, surfactants, infusing it with a vacuum to the content in the formed pins 60-nee 5 min, mostly 5-25 min, and subsequent drying.

Unlike the prototype of the fibrous suspension in the beginning of the dehydration contains 60-80% air (prototype 10-30%) and dehydration are under the influence of gravitational forces, and not under vacuum, as is done in the manner of the prototype.

The set of features of the method is quite simple technical way to obtain porous fibrous monolithic material with exceptionally low overall density and with different density, thickness: density of the material at its surface in 5-20 times greater than the density of the material as a whole. This became possible thanks to the high content of air in water of the fibrous suspension in the beginning of his dehydration (60-90%), and due to the fact that the process of dehydration on the grid, and thus molding the material under the action of gravitational forces within 5-25 minutes, but not less. In the way that excluded any physical effect on the foam in the stage of molding material, whereas in the prototype foam impact multiple transient pressure differentials to cause the outflow of water, resulting in the destruction of the bubbles of the foam.

The time of dehydration in the fir range, but in any case, this should be sufficient time to complete the process of forming the structure of the material due to the weave of the fibers while water drainage under gravity and for the formation of the surface layer of the material due to adsorption of molecules of surface-active substances, small fibers and binder particles on the surface of the section of material and air.

To prepare aqueous fibrous suspension using the following materials and reagents. As the fiber material may include wood pulp such as bleached sulfate (GOST 14940-75), chrysotile asbestos (GOST 12871-83), basalt fiber (PCT Ukraine 1970-86), polyester fiber (TU 6-06-0172-87), fiber, polyaramid threads (TU 6-06-0200-84), fibrous polymer film spanning polyphenylen softlimit (TC 6-06-I-80). As a binder, it is recommended latex of synthetic rubber "Neapol (TU 38.103581-85), silicone lacquer brand CO-08 (GOST 15081-78), KO-87 (THE 6-02-885-79), or polyvinyl acetate dispersion (PVA) (TU 18992-80). As surface-active products in fibrous suspension can be entered detergents progress (TU 38-10719-77), sulfinol (STU 108-37-60) and other surfactants.

If necessary the, antioxidants, biocides, water-repellent and fire-resistant substances, foam stabilizers, etc.

P R I m e R 1. 50 grams of bleached Kraft pulp was dispersed in a pulper to the degree of grinding of the 19aboutSHR administered 100 ml of a 50% aqueous solution of polyvinyl acetate dispersion and stirred for 1 min, then load 180 g of polyester fibers and lead to dispersion for 3 minutes In the mixture injected 100 ml of surfactant Progress and continue mixing of the composition to achieve the content of air in it 90% To stabilize the foam is injected polyacrylamide.

The resulting aqueous fibrous foam suspension is poured into a mold with mesh bottom, which is molded and simultaneously dewatered material of the porous structure due to removal of water under gravity. Molding material and its dehydration lead for 15 min, after which it is subjected to drying in two stages: first at a temperature of 90aboutWith, then, when 130aboutC. the resulting casting experience on thermal conductivity according to GOST 17177-87. To determine the density of the material near the surface, it is separated (cut) the top layer of a thickness of 30-60 μm, weighed and calculated by the density.

Examples 4,8,9,13,14 are given for comparison and show that in the case of reducing the amount of air in suspension up to 30% (examples 4,8,13) with the same composition, time of dewatering and drying thermal conductivity of the material increases to 0,054-0,065 W/maboutCompared to the 0,042-0,048, and the density of the material as a whole increased from 8.6 to 11.2 kg/m3to 47.3-71,3 kg/m3.

If the dehydration be reduced to 30 (example 14) and the sample is immediately placed in a drying, due to the high content of liquid, which boils, the sample is destroyed,

The increase in time of the dehydration of the sample over 25 min (example 9) significant effect does not.

The proposed material has:

extremely low density (8-11 kg/m3);

good structural properties;

satisfactory conductivity.

The process is relatively simple equipment design.

For the manufacture of the material can be used in a wide range of fibres and waste of their production.

1. Insulating fibrous material, made of intertwined and interconnected fibers, binder and surfactant volden monolithic density at its surface, in 5-20 times higher than the density of the material.

2. A method of manufacturing a fibrous insulation foam, including the preparation of an aqueous suspension of fibers, binders, surfactants and saturating it with air to form foam, molding material with simultaneous dehydration and subsequent drying, characterized in that the saturation of the air is carried out until the content in the foam 60-90% and dehydration are under the influence of gravitational forces for at least 5 minutes, mostly 5-25 minutes

 

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