RU2233300C2 - Method of paste filler production - Google Patents

Abstract

FIELD: building materials production, particularly for producing paste filler composition and for production process modernization.

SUBSTANCE: method for producing highly-filled paste filler used for room interior finish involves preparing aqueous solution including cellulose ester, preferably hydroxyethyl cellulose ester, laundry soap and specific-purpose additives; feeding aqueous solution simultaneously with supplying chalk in flow-type continuously acting double-auger mixer inside which zones of intensive shear stresses alternate. Number of zones is from 1 to 3. Shear rate in above zones is 300 - 1000 sec^-1; summary residence time in above zones is 1 - 2 sec.

EFFECT: reduced time of paste filler production, possibility of using chalk with different dispersiveness in accordance with delivery conditions, increased adhesion properties of ready paste filler, enhanced quality of interior finish.

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Description

The invention relates to the field of production of building materials, namely putty compositions, which are highly filled pastes used in construction for interior decoration, and can find wide application in the field of production and modernization of production of such compositions.

A known method of obtaining a putty, protected by RF patent No. 2167177, publ. 2001, In accordance with the known method, 0.24-0.3 wt. including plasticizer, mixing is carried out in an apparatus with a stirrer at a speed of 180 rpm and with constant stirring in the same mode, calcium carbonate in an amount of 50-70 parts by weight, clay 1-5 parts by weight, mica are successively introduced into the solution 1-11 parts by weight, hydroxyethyl cellulose and hydroxypropyl methyl cellulose, 0.1-0.5 parts by weight and latex or an aqueous polymer dispersion of 1.5-10 parts by weight; after stirring, water is additionally added until a viscosity of 38000-655000 mPa · s is achieved. In the particular case of the method, the resulting composition in order to increase its density is evacuated for 10-30 minutes to 0.05-0.2 atm. This method cannot provide homogenization of the resulting putty, and therefore its high technological and operational indicators. In addition, this method provides for periodic analysis of technological samples for viscosity to calculate the required amount of water to achieve a given viscosity, which greatly complicates the process and reduces its productivity.

The closest solution to the claimed is a method of obtaining putty for finishing work, described in copyright certificate No. 649733, publ. 1979, the Method consists in preparing an aqueous solution of sodium salt of carboxymethyl cellulose concentration of 4%, mixing it with an aqueous solution of laundry soap as a surfactant (hereinafter referred to as surfactants), tall pitch, chalk and subsequent grinding on a paint grater. To obtain a high-quality product, this method should include stages of sifting and soaking of chalk, which is associated with known technological difficulties, however, even the use of sifted and soaked chalk, repeated grinding can not ensure uniform distribution of the components in the composition, the method cannot provide the necessary homogeneity and plasticity of the material, as a result, the resulting putty cannot be used for high-quality external surface finish. In addition, the method is characterized by high duration, low efficiency and complexity.

The invention consists in the following.

The technical problem to which the claimed invention is directed is the development of modes and hardware design of a continuous method for producing a putty, which is a highly filled aqueous system that provides fast and high-quality mixing of liquid and solid components and, thus, high technological and operational performance of the resulting product.

The technical result of the claimed invention is to reduce the time it takes to putty when using chalk of various grindings as a filler in the delivery state, increase the adhesive properties of the resulting putty, improve the quality of the external finish when applying putty to the surface, in particular, when leveling and correcting surface defects.

The technical result is achieved by the fact that according to the claimed method, first prepare an aqueous solution consisting of cellulose ether, laundry soap as a surfactant, various target additives (in particular, additives that increase the resistance to the appearance of fungal microflora), and then the prepared mixture is supplied simultaneously with the supply of chalk in a continuous flow twin-screw mixer, characterized by a certain number of zones of intense shear stress. These zones are created by special working elements located on the shafts of a twin-screw mixer (augers with right and left threads and various steps, trihedral cams, discs). Passing through zones of intense shear stress, the processed mixture acquires plasticity and is homogenized. The compression and shear stresses arising in the processed mixture increase the mixing intensity of the liquid and solid components of the mixture, create conditions for the splitting of chalk particles of medium and large fractions, which increases the contact surface and the distribution of cellulose ether, laundry soap and target additives relative to chalk. The maximum effect is achieved when the material is processed in three zones of intense shear stresses, while in the first zone there is a coarse grinding of chalk, in the second zone - mixing of the components, in the third zone - homogenization of the mixture.

The number of zones of intense shear from 1 to 3 is due to the fractional composition of the chalk used and its amount.

The shear rate achieved from 300 to 100 s ^-1 is determined by the amount of chalk introduced.

The extremely uniform distribution of the aqueous solution of cellulose ether in the solid phase of the chalk increases the homogeneous state of the resulting putty. The homogeneous nature of the mixing of the putty components with the preliminary transfer of the chalk into the finely dispersed phase provides a large area of wetting of the total surface of the microparticles of the chalk with an aqueous solution of cellulose ether, which improves the appearance of the finish when using putty and increases its strength (adhesive and cohesive) indicators.

The predominant use of hydroxyethyl cellulose as a cellulose ether in the present method over other cellulose ethers used to obtain known compositions is due to the improved technological and operational characteristics of the resulting putty, which provides a high-quality surface layer on non-plastered surfaces with high adhesive and cohesive properties. For the implementation of the invention, cellulose ether can also be used, in particular methyl cellulose, sodium carboxymethyl cellulose.

A method of obtaining a putty is as follows. Initially, an aqueous solution is prepared consisting of water (34.3-41 parts by weight), cellulose ether (0.3-3.2 parts by weight), laundry soap (0.2-2.5 parts by weight) .) and target additives (0.1-0.2 parts by weight), which is then fed into a continuous twin-screw flow mixer. Chalk (58-70 parts by weight) is fed simultaneously into the mixer from the feed hopper. The ratio of the mass flow rates of the prepared aqueous solution and chalk is regulated by a smooth change in the supply of the aqueous solution using pumps.

The continuous continuous twin-screw mixer has two shafts rotating in one direction, on which screw, cam and disk elements are mounted, which are in mutual engagement. The gap between the inner surface of the mixer body and the elements is minimal, which ensures good mixing and grinding of liquid and loose components while the mixer is self-cleaning. The total residence time of the composition in the mixer is from 5 to 10 seconds.

The claimed method using a continuous continuous twin-screw mixer allows you to organize a highly efficient production method.

The resulting putty is a white paste-like mass, which when applied to the surface forms a thin even layer without peeling and cracking; the viability of the putty obtained is 300-400 days, the drying time is 1.0-1.5 hours.

Evaluation of the advantages of the proposed method was carried out by measuring the average particle size of the dispersed phase and the adhesive strength of the obtained putty in shear mode on wooden and metal samples.

The invention is illustrated by the following examples.

Example 1

An aqueous solution of methyl cellulose with a concentration of 1.0% and an aqueous solution of soap with an economic concentration of 0.3% are prepared, and chloramine is added therein in an amount of 0.05 parts by weight. per 100 parts by weight aqueous solution. The prepared aqueous solution and chalk are continuously dosed into a continuous ASH twin-flow in-line mixer with one zone of intense shear stress; the achieved shear rate in the specified zone is 300 s ^-1 ; residence time in the specified zone -1 s.

Example 2

An aqueous solution of the sodium salt of carboxymethyl cellulose with a concentration of 1.0% and an aqueous solution of soap with an economic concentration of 0.3% are prepared, and a borax in the amount of 0.1 wt. per 100 parts by weight solution. The prepared aqueous solution and chalk are continuously dosed into a continuous ASH twin-flow in-line mixer with two zones of intense shear stress; the achieved shear rate in the specified zone is 300 s ^-1 ; the residence time in the specified zone is 1.5 s.

Example 3

An aqueous solution of hydroxyethyl cellulose with a concentration of 1.0% and an aqueous solution of soap with an economic concentration of 0.3% are prepared, 0.1 ml of chloramine are also added thereto. per 100 parts by weight solution. The prepared aqueous solution and chalk are continuously dosed into a continuous ASH twin-flow in-line mixer with three zones of intense shear; the achieved shear rate in the specified zone is 1000 s ^-1 ; stay in the specified zone - 2 s.

Example 4 (in accordance with the prototype)

The amounts of sodium salt of carboxymethyl cellulose, laundry soap, chloramine and water are weighed in accordance with Example 3 and mixed in a tank reactor with a stirrer. The estimated amount of chalk is sieved and soaked in water. The prepared solution is mixed with chalk, and then the mixture enters the millstone CO-110 A, intended for grinding chalk pastes. After grinding on the paint grater, the finished product is obtained.

The table shows the properties of the putty obtained in accordance with the claimed method and method in accordance with the prototype.

BIBLIOGRAPHIC DATA

1. RF patent №2167177, publ. 2001 year

2. USSR Author's Certificate No. 649733, publ. 1979 year

Claims (2)

1. The method of producing putty by mixing an aqueous solution of cellulose ether, laundry soap and target additives with chalk, characterized in that the mixing is carried out in a continuous flow twin-screw mixer when alternating zones of intense shear stresses in the mixer, while the number of zones in which intensive shear forces equal to 1-3, the achieved shear rate in these zones is 300-1000 s ^-1 , and the total residence time in these zones is 1-2 s. 2. The method according to claim 1, characterized in that hydroxyethyl cellulose is used as the cellulose ether.