RU2540747C1 - Dry schungite-based composition to produce materials with unique combination of properties (schungilite) - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: invention may be used to manufacture wear-resistant waterproof heating coatings, such as self-levelling warm non-burn cast-in-place floors in residential and production buildings, sports, shopping, exhibition rooms, iced sites, staircase steps, ramps, to manufacture aesthetic cast radio-screening products and structures, and is also recommended as a finishing material in healthcare institutions. A dry schungite-based composition for production of materials with a unique combination of properties (Schungilite) includes, wt %: caustic magnesite powder - 20.3-32.2; caustic brucite powder - 8.7-13.8; polycarboxylate powder - 0.5-1.5; powder of vinyl acetate/ethylene copolymer - 0.5-3.0; powder of zinc stearate - 0.6-1.8; polydispersed schungite - balance.

EFFECT: increased coefficient of water resistance, crack resistance, strength, reduced water absorption, abradability, higher adhesion to various surfaces.

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Description

The invention relates to the building materials industry, and the composition can be used for the manufacture of environmentally friendly wear-resistant coatings, warm, non-burn bulk floors of residential and industrial premises, exhibition, sports, trading floors, heating coatings of icy sidewalks, stairs, platforms, ramps. It is recommended to use shungilite as a finishing material in the premises of medical institutions (hospitals, resorts, sanatoriums, etc.), as well as in the production of aesthetic cast radio-shielding products and structures.

Known polymer composite repair material [1], including:

1. The base part based on epoxy resin ED-20 and a fine filler and a curing part based on polyethylene polyamine and the same fine filler, the base part contains: epoxy resin ED-20 and as a filler a mixture of aerosil selected from the group consisting of Aerosil 175 or Aerosil 380, with shungite, silicon carbide, tungsten carbide and carbon nanotubes, in the following ratio of the components of the base part, parts by weight: epoxy resin ED-20 100-120; Aerosil 2-8; shungite 1-2; silicon carbide 1-3; tungsten carbide 0.5-1.2; carbon nanotubes are 0.1-0.5, and the curing part contains polyethylene polyamine, the plasticizer is a mixture of dibutyl phthalate with triethylene glycol in a weight ratio of 45-55 and 55-45, respectively, and as a filler a mixture of aerosil selected from the group consisting of Aerosil 175 or Aerosil 380, with shungite, silicon carbide, tungsten carbide and carbon nanotubes in the following ratio of components of the curing part, wt.h: PEPA hardener 33-40; plasticizer 35-40; Aerosil 3-8; schungite 0.4-1.0; silicon carbide 0.4-1.0; tungsten carbide 0.5-1.2; carbon nanotubes 0.1-0.5 with a ratio of resin and hardener corresponding to a stoichiometric proportion for epoxy groups and tertiary amines.

2. The material according to claim 1, characterized in that it contains a finely divided filler with the following particle sizes:

shungite from 500 to 1500 nm,

silicon carbide from 100 to 700 nm,

tungsten carbide from 100 to 700 nm,

carbon nanotubes from 5 to 50 nm.

This material has a low weight, high physical and mechanical characteristics, is heat-resistant and has increased thermal conductivity, which makes it possible to use it in various fields of mechanical engineering when repairing worn and broken parts of machines, assemblies and equipment.

The disadvantages of this polymer composite material are: high viscosity, which does not allow using it as coatings, rather complicated composition and technology of obtaining the material, high cost.

Known composite material based on schungite and a method for its production [2]. Composite material includes, wt.%: Building gypsum binder or a mixture of building and high strength gypsum binders - 18-38, calcium hydroxide - 0.5-1.0, plasticizer - sodium polycarboxylate - 0.5-0.8, setting retarder - amidox - 0.2-0.5, natural shungite crushed stone with a particle size of 5-20 mm - 51-74 and water - the rest.

The composite material according to this invention has good strength properties, is electrically conductive, causes the absorption of particulate and electromagnetic radiation, and also has antiseptic and biocidal properties.

The disadvantages of this composite material are that gypsum binders filled with shungite crushed stone with a particle size of 5-20 mm do not allow a highly mobile, self-leveling mass spreading over a large surface in a thin layer. In addition, gypsum binders do not have high adhesion to the surfaces of building materials of various nature, especially to concrete, ceramics, natural stone.

Known dry building mixture [3], including a component containing active magnesium oxide - caustic magnesia powder, wt.% - 15-40; a modifying additive (polymer redispersible powder - homo- and copolymers of vinyl acetate or ethylene vinyl versatate, silica fume or silica flour) - 0.5-10; as a filler contains the natural mineral shungite - the rest.

This building mixture allows you to obtain materials with combinations of various properties: high strength, shrinkage resistance, conductivity, protection against electromagnetic radiation and from the penetration of radon gas, frost resistance, oil-gas resistance. This invention is the closest in technical essence and we have chosen as a prototype.

The dry mortar proposed in the prototype has the following disadvantages:

- there are no data characterizing the properties of the viscous flow state of the closed mixture (mobility, viability, uniformity) and data on the quality of the forming surface of composite materials obtained from it;

- information on the properties of composite materials is fragmentary; no data on abrasion, adhesion to surfaces of different nature, water absorption, water resistance, bending strength and axial tension;

- the composition of the dry mixture does not include components and special additives that would provide protection against the formation of whitish "efflorescences", materials that sharply appear on a black background and reduce their quality.

The aim of the invention is the creation of an environmentally friendly dry composition based on shungite, which, when mixed, has high mobility and the property of self-leveling, and when cured in air it quickly gains strength, forming an aesthetic waterproof material with low abrasion and with high adhesion to the surfaces of various building materials, while maintaining this high mechanical strength, electrical conductivity and shielding properties.

This is achieved by the fact that a dry composition based on shungite to obtain materials with a unique combination of properties (“Shungilite”), including active magnesium oxide - caustic magnesite powder, a modifying additive and the natural mineral shungite, is characterized in that the active magnesium oxide is additionally taken in the form of caustic brucite powder, the modifying additive includes polycarboxylate superplasticizers and methyl acetate / ethylene copolymer and a hydrophobizing agent - zinc stearate powder, and the natural mineral shungite is taken in polydisperse nom state in the following ratio of components, wt.%:

caustic magnesite powder 20.3-32.2 caustic brucite powder 8.7-13.8 modifying additive: polycarboxylate powder 0.5-1.5 methyl acetate / ethylene copolymer powder 0.5-3.0 zinc stearate powder 0.6-1.8 polydispersed shungite rest

Shungite rocks are unique natural polymineral nanotechnological compounds that contain an amorphous carbon substance called shungite substance (SH). BC has an unusual structure, namely, that carbon is in it in the form of a new modification - fullerene and fullerene-like forms. Fine crystalline silicates are evenly distributed in this amorphous carbon matrix. Unique structural features give shungite a complex of specific properties: electrical conductivity, ability to shield electromagnetic radiation, high mechanical compressive strength; shungite is a good sorbent, antiseptic and biocidene, and its healing properties have been known and clinically confirmed since ancient times. The presence of mineral phases of various polarity (nonpolar carbon, polar silicates, aluminosilicates, etc.) in shungite rocks give the rocks the property to combine with both inorganic and organic substances. Therefore, shungite can be used as a filler or filler in composite materials on various binders. The properties of the composition are determined not only by the content of shungite in it, but also by a number of other factors: the nature of the binder, its ability and method to associate with the carbon component, the dispersion of shungite, the interaction of shungite particles and binder with modifying additives of the composition.

Thus, the electrical conductivity of the magnesia-shungite composition is determined both by the content of schungite filler in it and the concentration of carbon in this rock, and by the fractional composition of shungite. The conductivity of dispersed shungite differs significantly from its conductivity in the integral (monolithic) state. In dispersed shungite, electrical conductivity is largely dependent on the contact resistance between the shungite particles. With an increase in the degree of dispersion of schungite, its conductivity decreases, since the number of contacts increases, and therefore, the contact resistance. The fractional composition of shungite also strongly affects the physicochemical, mechanical, and other properties of the magnesia-schungite composition: mobility of the mass and its casting properties in a viscous-flowing state, and in the cured composition, on density, strength, crack resistance, adhesion to surfaces of various nature, abrasion . The optimal values of electrical conductivity, physico-chemical and other properties in this invention are provided, to a large extent, using polydisperse shungite. The fractional composition was calculated and selected so that the schungite particles were densely placed in the voids of the magnesian binder (in the voids of magnesium hydroxochlorides), and the quantitative and fractional composition of the finely dispersed part ensured optimal mobility of the self-leveling closed mass of the composition and obtaining material from it with an aesthetic surface. This was achieved by using a mixture of shungite fractions: 0.1-1.0, 5.0-30, 200-1000 microns, taken in a ratio of 1: 2: 4, respectively. Dispersion of schungite was determined using a Fritsch Analysette 22 NanoTech laser particle size analyzer.

The work was carried out using shungites of the Zazhoginsky and Maksovsky deposits of Karelia with a content of 29-32 wt.% Carbon substance.

The main astringent component of the composition — caustic magnesite — was used in a mixture with a small amount of caustic brucite. Caustic brucite has a shorter start and end time of "setting" in comparison with caustic magnesite, and its additives regulated the viability of the composition in a highly mobile state. The above amounts of caustic magnesite and caustic brucite in a dry composition are necessary and sufficient to obtain a movable mass when mixing, in which the input components are bonded together, and when cured in air, the mass forms a strong stone material.

The invention used caustic magnesite of OJSC “Combine Magnesite” (Satka, Chelyabinsk region), GOST 1216-87, and caustic brucite was obtained in the laboratory of Moscow Mining University by moderate firing of magnesium hydroxide Mg (OH) 2.

Powdered modifying additives of polycarboxylate and ethylene methyl acetate copolymer at concentrations of 0.5-1.5 and 0.5-3.0 wt.%, Respectively, ensured high mobility of the composition in the closed state, and upon curing, its particles and superplasticizer particles formed together with polydisperse schungite particles aesthetic uniform surface of the material. Higher concentrations of these additives reduced the mechanical strength of the composition, electrical conductivity and aesthetic qualities.

The introduction of a hydrophobic powder of zinc stearate in a concentration range of 0.6-1.8 wt.% Increased water resistance and reduced water absorption of the composite material. At zinc stearate concentrations above 1.8 wt.%, An excess of the latter was rejected by the matrix, and at concentrations below 0.6 wt.% The additive did not significantly affect the amount of water absorption and water resistance of the material.

The abrasion resistance of the obtained composite materials was measured at the Moscow University of Civil Engineering on disk-shaped samples with a diameter of 10-12 cm; sample load - 1 kg.

The specific volume resistance of the materials was measured both on alternating and direct current. Alternating current: 1000 Hz, 1 V; 1000 Hz, 50 mV; 100 Hz, 1 V; 100 Hz, 50 mV. Direct current: voltage 30 V, 60 V. The samples had the shape of a rectangular parallelepiped 10 cm long and a cross-sectional area of 1 cm ² . During measurements, brass plates 0.2 mm thick were glued to the opposite faces with conductive glue (Kontaktol, Keller).

Measurement of the adhesion strength of the compositions with bases of various nature (adhesion) was carried out according to GOST 31356.

Water absorption of composite materials was determined according to GOST 12730.3, softening coefficient (water resistance) - according to GOST 10060.0.

The crack resistance of the compositions was investigated using a light microscope on samples soaked in water for 4 days.

Measurements of mechanical strength were carried out on samples in the form of beams 4 × 4 × 18 cm in size.

The technology for obtaining a dry construction composition based on schungite consists of the following operations: strictly dosed amounts of active magnesium oxide in the form of powders of caustic magnesite and caustic brucite are mixed in a mixer together with a modifying additive consisting of superplasticizers and water repellent, polydispersed schungite (filler) is introduced into the mixture, and mix again for 5-7 minutes. The resulting dry composition is packaged in waterproof bags of 25-50 kg or big bags of 800-1000 kg.

The dry composition can be used directly at the construction site. It is mixed by bischofite - a solution of magnesium chloride (MgCl2) with a density of 1.1-1.3 kg / l, the optimum density is 1.19-1.22 kg / l.

Mixing is carried out with paddle mixers in containers of the required volumes until a highly mobile mass is formed, self-leveling under the influence of gravitational forces. The minimum coating thickness made from the dry composition is 3 mm (direct spill over the surface). Thinner coatings can be applied to the surface using a roller, brush or spray. Coatings with a thickness of 1 cm and above can be obtained using limiters (pouring mass by sectors).

The moving mass can be poured into molds of any sizes and configurations and various products can be obtained. In the form, the mass is kept for 5-6 hours, after which it is removed and left in the air until a full set of strength.

The resulting compositions are quick hardening. During the day they gain 40-45% of maximum strength.

Examples of obtaining a dry composition and its mixing.

Example 1

To prepare a batch of dry composition in an amount of 100 kg, 20.3 kg of caustic magnesite, 13.8 kg of caustic brucite are taken and mixed in a mixer with 0.5 kg of polycarboxylate, 1.5 kg of vinyl acetate / ethylene copolymer, 0.6 kg of zinc stearate, then 63.3 kg of polydisperse schungite are introduced into the resulting mixture and mixed again for 5-7 minutes.

The finished dry composition is closed with a bischofite solution with a density of 1.19 kg / l until a highly mobile mass with a self-leveling surface is formed. The minimum layer thickness on a flat substrate is 3 mm.

Example 2

To prepare a batch of dry composition in an amount of 100 kg, 26 kg of caustic magnesite, 11 kg of caustic brucite are taken and mixed in a mixer with 1.0 kg of polycarboxylate, 2.0 kg of vinyl acetate / ethylene copolymer, 1.2 kg of zinc stearate, then into the resulting mixture 58.8 kg of polydispersed schungite are introduced and mixed for 5-7 minutes.

The finished dry composition before use is shut on a bischofite solution, as described in example 1.

Example 3

To prepare a batch of dry composition in an amount of 100 kg, 32.2 kg of caustic magnesite, 8.7 kg of caustic brucite are taken and mixed with 1.5 kg of polycarboxylate, 3.0 kg of methyl acetate / ethylene copolymer, 1.8 kg of zinc stearate, then the resulting mixture is injected with 52.8 kg of polydisperse schungite and stirred for 5-7 minutes. The prepared dry composition is closed with a bischofite solution as described above.

The properties of the resulting compositions are summarized in table.

The table below does not reflect another important property - the radio-shielding ability of the compositions. All shungite-containing composite materials with a magnesian binder cause a weakening of electromagnetic energy in the range of more than 100 MHz at a level of 100 dB. In this case, the shielding ability increases with an increase in the oscillation frequency.

The dry composition based on shungite proposed in the invention allows, as the table illustrates, to obtain materials with a unique combination of properties:

- quick-hardening, with a self-forming aesthetic surface, not requiring additional machining;

- with super low attrition;

- high adhesion to surfaces of different nature: concrete, ceramics, natural stone;

- low water absorption, high coefficient of water resistance and crack resistance;

- electrical conductivity, which can be changed over a wide range;

- radio-shielding properties;

- high (for self-leveling compositions) mechanical strength.

It should be assumed that the composite materials created have healing and healing properties, since schungite is used as a filler, and the composition is mixed with a solution of magnesium chloride, which is the basis of sea salt.

The claimed composition of the dry composition based on shungite and its properties are interconnected by a single inventive concept, leading to the achievement of the results and allowing to create compositions with a given set of properties. Such a possibility for the prototype is very limited due to insufficient knowledge of the properties of materials and the fragmentary nature of the information presented in general (table).

The most important advantages of the dry composition of this invention over the prototype and analogues are: self-formation of a smooth homogeneous surface, a quick set of composition strength, aesthetics that remain even after contact with water (lack of "efflorescence"), ultra-low abrasion, widely varying resistivity and its more low values, that is, a higher electrical conductivity of the obtained materials.

Information sources

1. RF patent No. 2386653 ¹³ , C2, 2008. Polymer composite repair material.

2. RF patent No. 2405749 ¹³ , C1, 2009. Composite material based on schungite and method for its preparation.

3. RF patent according to cl. C04B 28/30, C04B 111: 20, 2003. Dry mortar (prototype).

Table Song Properties Example No. The composition, wt.% Highly mobile composition Solid composite Kaustich. magnesite and brucite Shungite Polycarboxylate Methyl acetate Zinc stearate Suttord spread spot, cm Life time, min general characteristics Density,
g cm ^-3 Mechanic strength, MPa Conductive δ _compression δ _bending δ _stretch. Rud. volumetric
Ohm m * one 34.1 63.3 0.5 1,5 0.6 25.5 40 Aesthetic hard material, uniform, smooth surface 1.71 31.8 9.5 4.2 29-50 (36) 2 37 58.8 1,0 2.0 1,2 26.0 55 Also 1.71 32,3 10.1 4.7 281-320 (296) 3 40.9 52.8 1,5 3.0 1.8 27.5 90 Also 1,69 36.5 10.6 5,4 1100-1430 (1370) four Prototype (RF Patent No. 2233255) It does not have self-leveling, self-forming properties Not aesthetic, high formation There is no data 10-35 There is no data 2000-5000 * Range of values of specific volume resistance of samples at alternating current (1000 and 100 Hz); in brackets - values at a direct current (voltage of 30 and 60 V).

Table (continued) Song Properties Example No. Abrasion resistance Adhesion to the bases of different nature, MPa.
The nature of adhesion * Water resistant Loss by weight (g) under a load of 1000 g Water absorption by weight,% Coeff. water resistance Crack resistance 100 cycles 200 cycles Abrasion,
g cm ^-2 Concrete Ceramics Granite one 0,030 0,068 0,020 > 3.9 character AT-3 > 4.0, AT-3 > 4.3, AT-3 4.0 0.98 Steady 2 0,038 0,084 0,022 > 4.1, AT-3 > 4.2, AT-3 > 4.5, AT-3 3.8 0.98 Steady 3 0,049 0,094 0,026 > 4.5, AT-3 > 4.5, AT-3 > 4.5, AT-3 3,5 1,0 Steady 4 (prototype) There is no data There is no data There is no data * The nature of the adhesion of the obtained composites (AT-3) indicates that there is a rupture of the material itself, and not its separation from the base.

Claims (1)

A dry composition based on shungite to obtain materials with a unique combination of properties (Shungilite), including active magnesium oxide - caustic magnesite powder, a modifying additive and natural shungite mineral, characterized in that the active magnesium oxide is additionally taken in the form of caustic brucite powder, the modifying additive includes superplasticizers polycarboxylate and methyl acetate / ethylene copolymer and water repellent are zinc stearate powder, and the natural mineral shungite is taken in a polydisperse state, with present state, wt.%:
Caustic Magnesite Powder 20.3-32.2 Caustic brucite powder 8.7-13.8 Modifying Additive: Polycarboxylate Powder 0.5-1.5 Vinyl Acetate / Ethylene Copolymer Powder 05-30 Zinc Stearate Powder 06-18 Shungite polydisperse Rest