RU2591063C1 - Wood bark-based nanocomposite structural material - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: present invention relates to the production of composite construction materials and can be used in making wood-mineral plates used as load-bearing walls, self-supporting walls and partitions, structural sound-and heat-insulation boards and panels. Nanocomposite material contains mineral filler, cement and water, wherein the wood matrix is formed from particles of 0.5-1.5 mm ultrafine pine bark, and the mineral filler of the structure is 50-250 Nm particles of nanosized basalt.

EFFECT: disclosed material is more environmentally friendly and has improved fire resistance and sound- and heat-insulating properties, improved physical and mechanical properties, is resistant to oxidative decomposition and biologically active media.

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Description

The invention relates to the field of obtaining composite building materials based on a nanosized mineral filler structure from ultrafine waste debarking wood and can be used in the manufacture of wood-mineral plates used as load-bearing, self-supporting walls and partitions, structural sound and heat insulation boards and panels, with improved environmental, fire hazard, sound and heat insulation properties, increased physical and mechanical characteristics, with resistance to oxidative degradation and biologically active environments.

Known cement chipboards (DSP) containing wood shavings of coniferous species, cement and mineral additives. The manufacturing process of such a plate includes mixing chips with minerals, high-grade Portland cement and water, forming a three-layer cement-bonded particleboard from two outer finely divided and one inner finely divided, and pressing. The composition of DSP TAMAK: hydration additives - 2.5%, water - 8.5%, wood shavings (1-10 mm) - 24%, Portland cement - 65%. (http://www.tamak.ru/cemento-struzhechnaya-plita/).

The disadvantages of such a plate are insufficient bending strength (9-12 MPa), high specific gravity (1.25-1.40 g / cm ³ ), high binder consumption (65%), high thermal conductivity (0.26 W / m ° C).

Known nanostructured wood-mineral composite material in the composition: wood - 55-40%, basalt - 30-40%, hydrated lime - 10-15%, water - the rest [RF Patent No. 2542025, IPC С04В 28/10, 2015]. The manufacturing process of this material includes: grinding softwood to a size of 1-2 microns, reinforcing them with basalt particles with an average particle size of 50-100 nm by mixing in baths with a basalt suspension using mixers with mixers, pumping and drying the wood suspension, mixing with hydrated lime, mixing with water, laying in molds, compaction on vibration tables, drying and curing in ovens.

The disadvantages of this material are increased energy consumption when chopping wood to a size of 1-2 microns, a long process of curing of lime (several years) compared with cement (28 days), the complexity of the process, increased cost (50 kg of quicklime - 250 rubles. , 50 kg of cement - 182 rub.), Lime without the addition of sand during hardening gives strong shrinkage and cracks, in addition, with poor mixing in the places of accumulation of lime, cracks form during hardening.

The closest solution to the claimed composition according to its technical nature (taken as a prototype) is the corolite (M. Tsyvin. The use of wood bark. - M.: Lesnaya industry, 1973 - p. 96) - a building material based on a mixture of high-moisture alloy bark coniferous wood (5-40 mm) treated with a mineralizer, Portland cement and water.

The disadvantages of this composition are low strength and thermophysical characteristics: breaking stress in bending - 0.5-0.7 MPa, breaking stress in compression - 0.5-3.5 MPa, thermal conductivity - 0.116-0.163 W / m · ° C, frost resistance - 25 cycles of alternate freezing, thawing, water absorption, reaching 93-115% after 24 hours.

The problem to which the invention is directed is to overcome these drawbacks, i.e. development of a new composite building material based on a nanodispersed mineral filler structure from ultrafine wastes of wood debarking with increased strength characteristics, an improved complex of physicomechanical and sound and heat insulation properties of final products.

The technical result is achieved by the fact that, as a wood matrix, the composition contains ground pine bark (Pinus silvestris L) with an average particle size of 1 ± 0.5 mm in an amount of 100 parts by weight, and dispersed waste from the production of basalt wool with an average particle size of 150 ± 50 nm in an amount of 15 parts by weight using mixers with mixers, pumping and drying wood slurry, mixing with hydrated lime, mixing with water, shaping, compaction on vibration tables, drying and curing in ovens.

The disadvantages of this material are increased energy consumption when chopping wood to a size of 1-2 microns, a long process of curing of lime (several years) compared with cement (28 days), the complexity of the process, increased cost (50 kg of quicklime - 250 rubles. , 50 kg of cement - 182 rub.), Lime without adding sand during hardening gives strong shrinkage and cracking, moreover, with poor mixing in the places of accumulation of lime, cracks form during hardening.

The closest solution to the claimed composition according to its technical nature (taken as a prototype) is the corolite (M. Tsyvin. The use of wood bark. - M.: Lesnaya industry, 1973 - p. 96) - a building material based on a mixture of high-moisture alloy bark coniferous wood (5-40 mm) treated with a mineralizer, Portland cement and water.

The disadvantages of this composition are low strength and thermophysical characteristics: breaking stress in bending - 0.5-0.7 MPa, breaking stress in compression - 0.5-3.5 MPa, thermal conductivity - 0.116-0.163 W / m · ° C, frost resistance - 25 cycles of alternate freezing, thawing, water absorption, reaching 93-115% after 24 hours.

The problem to which the invention is directed is to overcome these drawbacks, i.e. development of a new composite building material based on a nanodispersed mineral filler structure from ultrafine wastes of wood debarking with increased strength characteristics, an improved complex of physicomechanical and sound and heat insulation properties of final products.

The technical result is achieved by the fact that, as a wood matrix, the composition contains ground pine bark (Pinus silvestris L) with an average particle size of 1 ± 0.5 mm in an amount of 100 parts by weight, and dispersed waste from the production of basalt wool with an average particle size of 150 ± 50 nm in an amount of 15 parts by weight

It was noted that in the production of bark-based composites, the granulometric composition of the aggregate plays a fundamental role in the strength and appearance of the material. The best aesthetic and strength indicators, in our opinion, will be obtained with a maximum fraction of bark fractions of 0.5-1 mm. The use of basalt wool production waste - screening of basalt, crushed to a particle size of 50 to 250 nm, in the wood composition provides a technical effect consisting in a significant increase in properties such as tensile, compressive, bending tensile strength, impact strength, and elastic modulus.

The invention is implemented as follows: pine bark, previously washed and soaked in distilled water at a temperature of 20 ° C for one day in order to remove mechanical impurities and reduce the content of water-soluble extractive substances, is dried to constant weight in an oven at 105 ° C for 6 hours and then pre-crushed to a size of 5-30 mm, which corresponds to the size of the waste debarking obtained from debarking machines OK-66M and K-26. Then it is dry-milled using any known method, in our case, on a ball mill with the following operating parameters: the number of steel grinding bodies 2 cm in size - 23 pcs., The rotation speed of the mill - 360 rpm, the grinding time - 1 minute. The bark thus prepared is mixed with a suspension obtained by sifting through a 5 mm sieve and grinding by wet grinding using any known method, in our case, a basalt screening ball mill. Wet grinding of basalt is carried out with the following operating parameters: the number of steel grinding bodies 2 cm in size - 23 pcs., The mill rotation speed - 420 rpm, grinding time - 2 hours. Mixing the cortex with the suspension is carried out mechanically for 20 minutes. At the end of mixing, the required amount of cement is supplied (not more than 30%), if necessary, water, and still mix for 5-7 minutes. The finished mixture is dosed by weight and fed to the paver for laying in the mold.

Products are molded in collapsible metal molds with pallets and removable board equipment. Before laying the mixture, the molds are thoroughly cleaned of dirt and lubricated with a thin layer of machine oil or special. It should be noted that the use of wood debarking waste and basalt wool production waste as a matrix and filler eliminates their utilization, which is important both from an economic and environmental point of view.

Claims (1)

 Composite material obtained from a mixture containing coniferous tree bark, cement and water, characterized in that the mixture contains ultrafine pine tree bark of 0.5-1.5 mm size and additionally a suspension obtained by wet grinding of basalt wool production waste to a nanometer size 50-250 nm, in the following ratio of components of the mixture, wt. hours: the specified bark - 100, the specified suspension in terms of dry matter - 15, and the cement content in the mixture is 30 wt. %, moreover, a matrix of said composite material is formed from pine bark