RU2448923C1 - Plaster gypsum dry construction mixture - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to the industry of construction materials and can be used in production of plaster gypsum dry construction mixtures for interior finishing of buildings for different purposes, including high-humidity facilities. The plaster gypsum dry construction mixture contains the following, wt %: gypsum plaster 75.95 - 88.44, construction lime 3-5, ceramsite dust 5 - 20, polyethylene oxide 1.0 -1.5, citric acid 0.039 - 0.041, starch ether 0.011 - 0.02.

EFFECT: high adhesion strength and water resistance of the plaster gypsum mixtures, wider raw material base owing to use of local mineral material and wastes without deterioration of consumer properties.

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Description

The present invention relates to the building materials industry and can be used in the manufacture of stucco mixtures for interior decoration of buildings for various purposes, including rooms with high humidity.

Known gypsum gypsum dry mortar, including calcium sulfate β-hemihydrate (gypsum binder), water-soluble methyl cellulose, a surfactant based on sodium alkyl sulfate, finely ground limestone, quicklime and tartaric acid (USSR copyright certificate No. 1652323, cl. 14, 05/30/91. Bull. No. 20).

The disadvantage of the stucco mixture is the low strength characteristics due to the insufficient amount of gypsum binder. An increased amount of filler may result in a reduced adhesive bond to the surface being trimmed.

Known gypsum mixture according to patent No. 2090533 (publ. 09/20/97), including semi-aquatic gypsum and the addition of alkaline effluents for the production of caprolactam based on dicarboxylic acids ShchSPK, it additionally contains a multidentate chelating ligand and trisodium phosphate in the following ratio, wt.%: Semi-aquatic gypsum 47 -72; the addition of alkaline effluents for the production of caprolactam based on dicarboxylic acids ShchSPK 0.2-0.8; multidentate chelating ligand 0.03-0.15; trisodium phosphate 0.05-0.1; water the rest.

The described composition has the following disadvantages: the stability of the composition due to its water-emulsion state is limited, in addition, the resulting coating has a low adhesive strength.

Known gypsum plaster dry building mix, which contains gypsum binder, sand from expanded vermiculite, lime, a hardening inhibitor - limonic acid, ether cellulose in the form of carboxymethyl cellulose, an air-entraining additive - sulfonol, superplasticizer (see, for example, KZ No. 115.02. 2002, 4 p.).

The described composition has the following disadvantages: low adhesive strength, the presence of ether cellulose and expanded vermiculite significantly increases the cost.

The closest analogue is the composition of dry plaster gypsum mortar, presented in patent No. 2237035 (RU), IPC ⁷ С04В 28/14, containing in wt.%: Gypsum - 90-92; perlite - 2.5-3.1; lime - 1.2-1.5; limestone flour - 4.0-5.0; hardening retarder - 0.035-0.045; ether cellulose - 0.13-0.16; redispersed powder - 0.018-0.03; air entraining additive - 0.008-0.015; starch ether - 0.09-0.1; technical sodium tripolyphosphate - 0.04-0.045.

The described composition has the following disadvantages: the resulting coating has a low adhesive strength, the use of stucco gypsum dry building mix is possible only in rooms with normal humidity conditions.

The objective of the invention is to increase the adhesion strength, water resistance of stucco gypsum dry building mixtures, as well as the expansion of the raw material base through the use of local mineral raw materials and production waste to reduce the cost of materials without compromising their basic consumer properties.

The result is achieved by the fact that plaster dry gypsum building mixture, including building gypsum, lime, a thickener - starch ether, a filler, a water-retaining component, a hardening inhibitor, according to the invention contains claydite dust as a filler, polyethylene oxide as a water-holding additive, as a moderator hardening - citric acid, in the following ratio of ingredients, wt.%:

gypsum building - 75.95-88.44;

lime - 3-5;

expanded clay dust - 5-20;

polyethylene oxide - 1.0-1.5;

citric acid - 0.039-0.041;

starch ether - 0.011-0.02.

Plaster gypsum dry mortar includes:

- building plaster according to GOST 125-79;

- lime according to GOST 9179-77;

- expanded clay dust - waste from the production of expanded clay gravel from cyclones and dust filters of rotary kilns, having the composition shown in table 1.

Table 1 Composition of expanded clay dust d, Å Mineral d, Å Mineral 17.60 Smectite 3,238 KPSH 10.00 Muscovite 3,189 Albite 7,102 Chlorite 2,948 Albite 6,378 Albite 2,854 Albite 5.00 Muscovite 2,711 Hematite 4,735 Chlorite 2,572 Smectite 4,480 Muscovite 2,456 Quartz 3,765 Albite 2,37 Chlorite 3.66 Albite 2,281 Quartz 3.57 Chlorite 2,236 Quartz 3,501 Albite 2,236 Quartz 3,342 Quartz 2,126 Quartz

- polyethylene oxide according to TU 6-05-231-341-88 (PEO-S (high molecular weight) produced by OJSC Kazanorgsintez);

- citric acid (C ₆ • H ₈ • O ₇ • H ₂ O) - a crystalline substance of white color, melting point 153 ° C, readily soluble, produced according to GOST 908-2004;

- starch ether according to GOST 20370-74.

Preparation of the dry mixture is as follows.

First, polyethylene oxide, which is a granular powder, is ground together with lime and expanded clay dust to a specific surface of 350-500 m ² / kg. Further, all components are loaded into the mixer and mixed to a homogeneous mass.

Testing of stucco gypsum dry mortar, mortar and mortar based on them was carried out in accordance with GOST 5802-86, TU 5745-001-61804221-2009. The mobility of stucco mortar mixtures was 12–13 cm, of putty mortar mixtures — 8–9 cm along the immersion depth of the StroyTSNIIIL cone.

The determination of the softening coefficient was carried out according to TU 21-0284757-90.

The compositions of dry gypsum building mixtures are shown in table 2.

The test results are shown in table 3.

table 2 Compositions of stucco gypsum dry mortar Name Composition 1 Composition 2 Composition 3 Prototype Gypsum plaster 75.95 83,44 88.44 90,095 Lime 3 5 5 3,255 Expanded clay dust twenty 10 5 - Citric Acid (Moderator) 0,039 0.04 0,041 0,025 Polyethylene oxide one 1,5 1,5 - Starch ether 0.011 0.02 0.019 0,07 Perlite - - - 3,1 Lime flour - - - 5,0 Cellulose ether - - - 0.16 Disperse latex powder - - - 0,03 Airborne Additive - - - 0.015 Sodium Tripolyphosphate - - - 0,045

Table 3 Physicotechnical characteristics of the compositions Name of properties Compositions Prototype one 2 3 Maximum particle size, mm 0.5 0.5 0.5 - Humidity of stucco gypsum dry mortar,% no more than 0.1 no more than 0.1 no more than 0.1 - Water demand,% 52 53 51 - Mobility, cm 7-11 8-12 7-10 Plastic Setting time, min 25-85 30-95 35-95 95 Vitality, hour 85 95 95 95 Average thickness mm 12 12 12 10 Permissible thickness, mm 40 42 44 40 The average density, kg / m ³ 1310 1330 1320 - Water retention capacity,%, not less than 97 98 98 - Compressive strength, MPa 6.2 6.5 6.2 6 Adhesion to base, MPa 0.5 0.55 0.4 Not less than 0.1 Softening coefficient 0.6 0.7 0.55 -

The data presented in table 3 show that this plaster gypsum dry mortar has a number of improved physical and mechanical characteristics compared to similar dry gypsum mortar: compressive strength, softening coefficient, adhesion to the base.

The introduction of a complex additive (lime and expanded clay dust) in the composition of dry gypsum building mixtures increases the softening coefficient due to the formation of insoluble minerals in the dry building mixture.

In addition, this invention also solves the environmental problem - the disposal of dumps for the production of expanded clay gravel, which currently does not find sufficient full application.

Thus, the use of the proposed composition of stucco gypsum dry mortar allows you to get a composition with improved performance properties, while utilizing the waste production of expanded clay gravel and cheaper products.

Claims (1)

Plaster dry gypsum building mixture, including building gypsum, lime, thickener - starch ether, filler, water-retaining component, hardening retarder, characterized in that it contains expanded clay dust as a filler, polyethylene oxide as a water-retarding additive, and citric acid as a hardening inhibitor in the following ratio of ingredients, wt.%:
gypsum building 75.95-88.44 building lime 3-5 expanded clay dust 5-20 polyethylene oxide 1.0-1.5 lemon acid 0,039-0,041 starch ether 0.011-0.02