RU2399602C1 - Raw mixture for manufacturing thermal insulating material and method of its preparation - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: raw mix contains, wt parts: ground wood 10.00, cement 37.50-38.80, liquid glass 1.66-1.80, polymethylene naphthalene-sulfacid sodium salt as superplasticiser 0.02-0.03, disodium salt of ethylene diamine tetraacetic acid as complexing additive 0.11-0.20 and foaming agent - synthetic foaming agent on the basis of alkylsulfates of primary fatty alcohols. Method for preparation of this raw mix is characterised.

EFFECT: production of thermal insulating material with medium density no more than 400 kg/m³ and preservation of its high heat insulation, technological, strength and eco-friendly properties.

3 cl, 2 tbl

Description

The invention relates to the field of construction, namely to concrete mixtures for the manufacture of heat-insulating material, and can be used as thermal insulation of heating mains, roofs, as well as for installing walls of various buildings, thermal insulation of floors of residential and public buildings.

A known raw material mixture for the manufacture of a thermal waterproof coating, including cement, latex, water glass, expanded polystyrene granules, fractions 0.14-0.63 mm - 30%, fractions 1.25-5 mm - 70%, bone glue, turpentine and water at the following ratio of components, parts by weight:

Cement 80-100 Latex 20-40 Liquid glass 5-15 Expanded polystyrene granules fractions of 0.14-0.63 mm - 30%, fractions of 1.25-5 mm - 70% 7-25 Bone glue 0.5-1.0 Turpentine 0.5-1.0 Water 40-80

(RF patent No. 2275346, CL 04B 41/45. Publ. 04/27/2006).

A disadvantage of the known mixture is the use of significant quantities of expensive synthetic polymers, in particular polystyrene, which during the operation of the product, as well as when exposed to high temperatures, can release toxic substances for humans, such as styrene, phenols, etc.

Known building material, molded (raw) mixture of which includes crushed moistened wood, cement, water glass and water in the following ratio of components, wt.%:

Shredded wood 65 Cement grade 400, 500 21 Liquid glass 3 Water rest

(RF patent No. 2163581, class C04B 40/00, C04B 28/02, C04B 18/26. Published. 02/27/2001).

A known method of manufacturing products from the above building material by chopping wood and sifting it into fractions with its subsequent moistening. Then the wood is mixed with cement and water glass, the raw material mixture is loaded into the mold and compacted by pressing. They attach the forms to the electrodes, connect a direct current with a periodic change of poles. The form with a lid and a tray are made of stainless steel with the possibility of using them as electrodes [RF Patent No. 2163581].

This raw mix and method of manufacturing products from it require sophisticated molding equipment and electrical processing to achieve the necessary strength of the final material, which significantly complicates the process and increases the cost of products.

Known raw mix for the manufacture of arbolite, including Portland cement, wood aggregate, water glass, water and saponified rosin in the following ratio, wt.h .:

Portland cement 1.3-1.6 Wood aggregate 1,0 Liquid glass 0.03-0.08 Water 1.44-1.77 Saponified Rosin 0.005-0.01

(USSR copyright certificate No. 1058955, class C04B 43/12. Publ. 07.12.83 Bul. No. 45).

A known method of preparing arbolite, including processing wood aggregate with liquid glass in an amount ^of _3/4 , followed by mixing it with Portland cement and water, introducing saponified rosin in the form of technical foam (foaming agent) stabilized by the remaining liquid glass, and re-mixing the components of the mixture [a. from. USSR No. 1058955].

The specified raw mix and method of its preparation are the closest in technical essence and the achieved result to the described invention. These technical solutions are characterized by insufficiently high product strength (more than 0.5 MPa) at an average density of 400 kg / m ³ .

The problem to which the invention is directed, is to obtain a heat-insulating material with an average density of not more than 400 kg / m ³ while maintaining its high thermal insulation, technological, strength and environmental properties.

The problem is solved in that the raw material mixture for the manufacture of heat-insulating material, including wood aggregate, cement, water glass, foaming agent and water, additionally contains polymethylenenaphthalene sulfonic acid sodium salt as a plasticizer and ethylenediaminetetraacetic acid disodium salt as a complexing additive, and as a synthetic foaming agent a foaming agent based on alkyl sulphates of primary fatty alcohols in the following ratio of components, ma S.ch .:

Wood aggregate 10.00 Cement 37.50-38.80 Liquid glass 1.66-1.80 Primary fatty alcohol alkyl sulphates 0.24-0.26 Polymethylene Naphthalene Sulfonic Acid Sodium Salt 0.02-0.03 Ethylenediaminetetraacetic acid disodium salt 0.11-0.20 Water 40.00-45.50

At the same time, wood waste fractions of less than 1 mm were selected as a wood filler. And also due to the fact that according to the method of preparing the raw material mixture for the manufacture of heat-insulating material, comprising treating the foaming agent with liquid glass and mixing it with the components of the mixture, a foaming agent based on alkyl sulphates of primary fatty alcohols in an amount of 2/3 of its predetermined volume is mixed with 2/3 parts of water and add polymethylenenaphthalene sulfonic acid sodium salt as a plasticizer and as a complexing additive - ethylenediaminetetraacetic acid disodium salt, mix and get a solution that is combined with cement in a rotary mixer at a rotor speed of 1000-1500 rpm to obtain a cement paste, and the remaining parts of the water and foaming agent are mixed with liquid glass and mixed in a rotary mixer at a rotor speed of 1000-1500 rpm / min until a dense foam is formed, which is mixed at a rotor speed of at least 800 rpm with a wood aggregate with a moisture content of up to 25%, the resulting wood pulp is mixed with cement paste at a rotor speed of at least 800 rpm before smooth IAOD.

The additional introduction of sodium salt as a plasticizer into the raw material mixture of polymethylene naphthalene sulfonic acid leads to the dilution of the cement paste, the splitting of cement flocs and an increase in the final strength of the product.

And the additional introduction of a complexing additive - ethylenediaminetetraacetic acid disodium salt, on the one hand, dilutes the mixture, increases its mobility and improves the mass transfer of calcium ions from the surface of the cement grain into the aqueous phase, where cement gel particles are formed, and, on the other hand, neutralizes the negative effect of extractive wood substances on the hydration activity of cement, increases the strength of the adhesive contact of the mineral matrix and wood aggregate. As a result, the density of the cement gel and the final strength of the product increase.

A synthetic foaming agent based on alkali sulfates of primary fatty alcohols contributes to high air absorption, which leads to an increase in workability of the mixture and a decrease in the thermal conductivity of the product.

The use of wood aggregate in the form of waste wood fractions of less than 1 mm makes it possible to obtain a homogeneous raw mix with high workability. As a result, there is no need to re-seal the freshly formed mixture. At the same time, wood fibers contribute to the stabilization of the cellular structure of the material, which improves the thermal insulation characteristics of the product.

The raw material mixture is prepared as follows.

Mix 2/3 of the volume of water with 2/3 parts of a foaming agent based on the alkali sulfates of primary fatty alcohols brand PB-2000. A plasticizer based on polymethylene naphthalene sulfonic acid of sodium salt of grade C-3 and a complexing additive of ethylenediaminetetraacetic acid of disodium salt of Trilon-B grade are dissolved in the resulting mixture. The resulting solution is shut cement and mixed thoroughly in a high-speed rotary mixer at a rotor speed of 1000-1500 rpm for 10-15 minutes The high rotor speed activates the cement, creates dense adsorption layers of the S-3 plasticizer and the Trilon-B complex-forming additive, and also activates the formation of air microinclusions in the mixture, which improve the workability of the mixture.

Then the remaining part of the water is combined with the remaining part of the PB-2000 blowing agent and liquid glass and mixed in a rotary mixer at a rotor speed of 1000-1500 rpm until a dense foam is formed. Combine dense foam with wood filler with a moisture content of up to 25% and mix at a rotor speed of at least 800 rpm. Dense foam at the same time facilitates the process of uniform distribution of water glass on the surface of the particles of wood aggregate. The resulting wood pulp is combined with previously prepared cement dough and mixed in a rotary mixer at a rotor speed of at least 800 rpm until the viscosity of the cement composition increases. The indicated rotor speed contributes to the separation of particles of wood aggregate, the destruction of the formed particles of the coagulum of liquid glass, which forms a strong adhesive contact of the wood fiber and the cement matrix. The obtained homogeneous viscoplastic mass is discharged into the molds or receiving hopper of the gerotor pump for filling technological cavities of building structures. They compact the raw material mass in the forms by the method of vibration compaction on a vibrating stand or with the help of immersion vibrators. The stripping strength of the products is achieved after 16-24 hours at an ambient temperature of 18-25 ° C.

The compositions of the raw mix according to the invention and the closest analogue (prototype) are shown in table 1, and their properties are shown in table 2.

Since the main component responsible for the strength properties of the material is the Trilon B complex-forming additive, several examples are given showing changes in the properties of the material with different contents of this component.

With the introduction of a complexing additive less than the specified limit, significant shrinkage occurs, the strength of the material decreases sharply.

With the introduction of more complexing additives, the mixture becomes difficult to mix. The molding properties of the material worsen, and the strength of the material also decreases.

Table 1 Components The content of components in the composition in parts by weight Prototype, parts by weight Composition 1 Composition 2 Composition 3 Composition 4 Composition 5 Wood aggregate 10.00 10.00 10.00 10.0 10.00 1,0 Cement 34.00 35.00 37.50 38.80 40.00 1.3-1.6 Liquid glass 1,64 1,66 1.70 1.80 1.85 0.03-0.08 Primary fatty alcohol alkoxylates foaming agent 0.22 0.24 0.25 0.26 0.3 - Plasticizer based on polymethylene naphthalene sulfonic acid sodium salt 0.01 0.02 0.02 0,03 0.04 - Complexing Additive 0.10 0.11 0.15 0.2 0.25 - Saponified Rosin - - - - - 0.005-0.01 Water 38.00 40.00 43.00 45.50 47.00 1.44-1.77

table 2 Properties The content of components in the composition in parts by weight Prototype, parts by weight Composition 1 Composition 2 Composition 3 Composition 4 Composition 5 The average density, kg / m ³ 300 300 350 400 600 400 The coefficient of thermal conductivity, W / m ° C 0.06 0.06 0,065 0.08 0.26 0.08 The limit of compressive strength, MPa 0.20 0.65 1.00 1,50 2.00 0.5

Reducing the wood content does not allow to achieve a given density and high strength. An increase in the content of crushed wood leads to an increase in the mixing time of the mixture, the density of the material does not decrease, but the strength characteristics deteriorate.

Combining cement with a solution of a foaming agent, a plasticizer based on polymethylene naphthalene sulfonic acid sodium salt and disodium salt of ethylene diamine tetraacetic acid in a high-speed mixer at a rotor speed of 1000-1500 rpm for 10-15 minutes is necessary to create vortex flows that activate the mutual friction of the cement cement particles them from hydration shells and the formation of organomineral complexes of organic substances and gel hydrosilicate particles. At the same time, active air entrainment into the cement paste and the formation of foam mass occur. The degree of air intake is regulated by the rotor speed and the duration of mixing.

Combining the remaining part of the water and the foaming agent with liquid glass in a rotary mixer at a rotor speed of 1000-1500 rpm allows to obtain high-fold fine-meshed foam in a short period of time. Fine-meshed foam combines well with wood aggregate with a moisture content of up to 25%. The high stability of the foam based on the specified foaming agent minimizes its destruction during the introduction of wood aggregate, prevents the absorption of the film fluid of the foam by particles of wood aggregate, and facilitates the uniform distribution of liquid glass over the surface of wood particles. To reduce the shrinkage of the foam in the process of combining with wood aggregate, it is advisable to reduce the rotor speed of the mixer to 800 rpm, but not lower, to prevent the aggregate particles from sticking together.

The indicated rotor speed should be maintained during the final combination of the foam cement mass and treated wood aggregate, on the one hand, to reduce the damaging effect of the aggregate on the previously formed structure of cement foam, and on the other hand, to prevent the aggregate particles from sticking together in the cement foam.

The technical result is to improve the physico-mechanical properties of the insulating material, namely the average density, coefficient of thermal conductivity and tensile strength in compression.

Claims (3)

1. The raw material mixture for the manufacture of heat-insulating material, including crushed wood, cement, water glass, foaming agent and water, characterized in that polymethylene naphthalene sulfonic acid is additionally added sodium salt as a superplasticizer and ethylenediaminetetraacetic acid disodium salt as a complexing agent, and as selected synthetic foaming agent based on alkyl sulfates of primary fatty alcohols in the following ratio of components, parts by weight:
wood aggregate 10.00 cement 37.5-38.8 liquid glass 1.66-1.80 primary fatty alcohol alkyl sulfates 0.24-0.26 polymethylene naphthalene sulfonic acid 0.02-0.03 sodium salt ethylenediaminetetraacetic acid 0.11-0.20 disodium salt water 40.0-45.50 2. The raw material mixture according to claim 1, characterized in that the waste wood fraction less than 1 mm is selected as crushed wood. 3. The method of preparing the raw material mixture according to claim 1, comprising treating the foaming agent with liquid glass and mixing it with the components of the mixture, characterized in that a synthetic foaming agent based on alkyl sulphates of primary fatty alcohols in an amount of 2/3 of its predetermined volume is mixed with 2/3 of water and add a plasticizer based on polymethylene naphthalene sulfonic acid sodium salt and a complexing additive based on ethylenediaminetetraacetic acid disodium salt, mix and get a solution that is combined with cement ntom in a rotary mixer at a rotor speed of 1000-1500 rpm for 10-15 minutes to obtain a homogeneous cement paste, the remaining parts of the water and foaming agent are mixed with liquid glass and mixed in a rotary mixer at a rotor speed of 1000-1500 rpm until a dense foam is formed, and then mixed at a rotor speed of at least 800 rpm with wood filler with a moisture content of up to 25%, the resulting wood pulp is combined with cement paste by mixing in a rotary mixer at a rotor speed of at least 800 rpm for 10-20 minutes.