RU2487096C1 - Gypsum composition for manufacturing of gypsum board sheets with higher resistance to temperature effect - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: gypsum composition includes gypsum, dry oxidised starch, technical lignosulfonate, a foaming agent, water and pre-watered (from 15% to 40%) swollen perlite sand of fine fraction from 0.16 mm to 1.25 mm.

EFFECT: increased resistance to temperature effect, namely increased time to damage of samples under high temperatures, which makes it possible to increase time for evacuation.

4 cl, 2 tbl, 2 ex

Description

Technical field

The present invention relates to a gypsum composition for the production of drywall sheets with high resistance to temperature. The invention provides increased resistance of drywall sheets to thermal effects, which leads to an increase in the time for the evacuation of people from residential premises before the destruction of building drywall structures.

State of the art

Plasterboard sheets with increased resistance to temperature are used as building and finishing materials in rooms with increased fire safety requirements for the implementation of internal partitions, suspended ceilings, for wall cladding, ventilation shafts, electrical panels and other things. The invention proposes the introduction into the gypsum composition of expanded perlite sand, which plays the role of an additional reinforcing component during temperature exposure. Considering that expanded perlite sand has adsorption properties, it is most often proposed in construction for mixtures with low solution mobility. So expanded perlite sand was proposed for the creation of fire-resistant plasters RU No. 2173309, for the manufacture of lightweight concrete RU 2399598, for the manufacture of gypsum dry gypsum plasters RU 2237036, for the manufacture of sound-absorbing plates in an amount of 7.5% (SU 885180 A, 11/30/1981, С04В 11 / 09.2 pp.), For the manufacture of heat-insulating products in the amount of 2.9% of the weight of gypsum (SU 1520034 A, 11/07/1989, С04В 11/00, 3 pp.).

In the material "Gypsum materials and products (production and use)", (Handbook edited by Ferronskaya A.V., Moscow, DIA, 2004, pp. 211-216), a composition for gypsum boards with high resistance to temperature, containing gypsum is known , dry modified (oxidized) starch, technical lignosulfonate, foaming agent, water, reinforcing additive. As a reinforcing additive, in this material, the use of fiberglass scraps no more than 10 mm long is proposed.

The closest set of features from the above examples to the invention, i.e. the prototype is a composition for drywall sheets with high resistance to temperature, containing gypsum, dry modified (oxidized) starch, technical lignosulfonate, foaming agent, water, a reinforcing additive. The proposed fiberglass trimming, used as a reinforcing additive, does not reduce the spread of gypsum mortar, which only fruitfully affects the strength characteristics of gypsum plasterboards. However, the used fiberglass trimming perform only the role of reinforcing drywall sheets and lead to an increased consumption of foaming agent upon receipt of drywall sheets.

In the present invention, it is proposed to use pre-flooded expanded perlite sand instead of fiberglass scraps, which makes it possible to produce gypsum plasterboards with increased temperature resistance, reduced weight, with the required loads and the required gypsum mixture without additional costs for plasticizer. Disclosure of invention

The preferred gypsum-containing product in the claimed invention are gypsum plasterboards with high temperature resistance.

The objective of the invention is the creation of a gypsum composition for drywall sheets with high resistance to temperature and with a load corresponding to GOST 6266-97. A gypsum composition for the production of drywall sheets is proposed, which includes: gypsum, dry oxidized starch, foaming agent, technical lignosulfonate, water and pre-flooded from 15% to 40% expanded fine perlite sand (according to GOST 10832-91) from 0.16 mm up to 1.25 mm. This range of humidity of expanded perlite sand allows you to conduct the manufacturing process of obtaining drywall sheets more safely for the health of workers. Depending on the requirements, the composition of the gypsum core may additionally include: fiberglass, setting accelerator, organic and inorganic gypsum modifiers and other known additives.

The proposed flooded expanded perlite sand with a specific fraction is provided based on the following:

a) expanded pearlite sand of fine fractions with a grain size from 0.16 mm to 1.25 mm allows you to get drywall sheets with the required loads, corresponding to GOST 6266-97. In addition, due to the introduction of a fine fraction, a more uniform distribution of grains occurs over the gypsum composition;

b) the use of a finer fraction (powder) leads to an increase in the density of drywall sheets and an increased consumption of materials;

c) the use of a larger fraction reduces the strength of drywall sheets;

d) the use of pre-flooded perlite sand from 15% to 40% only slightly increases the water / solid ratio, which also has a beneficial effect on the strength characteristics of gypsum plasterboard;

e) the use of expanded perlite sand with a moisture content of less than 15% leads to an increase in the water / solid ratio, as a result of which the strength characteristics of drywall sheets are reduced;

f) the use of expanded perlite sand with a moisture content of more than 40% is not technologically convenient, since clumping and freezing of the product occurs during dosing using equipment for dispensing bulk components.

The implementation of the invention

According to the claimed embodiment of the present invention, there is provided a gypsum composition for the production of gypsum plasterboards with high temperature resistance, which includes: gypsum from G6 according to GOST 125-79, dry oxidized starch with a pH from 1 to 7.5, a foaming agent (based on ammonium alkyl ether sulfate or other foaming bases), a plasticizer (based on dry sodium lignosulfonate and its solution or other plasticizing additives), water and an additionally pre-flooded expanded perlite esk. Depending on the requirements, the composition of the gypsum core can be additionally introduced: fiberglass, setting accelerator, organic and inorganic gypsum modifiers and other known additives.

Below is one of the possible options for the preparation of laboratory samples of drywall sheets.

All products are weighed with an accuracy of 0.01 g. Sample preparation includes the following steps:

At the first stage, 60 g are taken from the total mass of water and 0.6 g of a foaming agent is dosed into it. The resulting mass is whipped with a mixer into the foam for 2 minutes until a foam volume of 0.8 to 1 liter is obtained.

At the second stage, the remaining water is poured into the container and a weighed plasticizer is loaded into it. The plasticizer is taken as a solution in terms of dry matter (the water introduced with the plasticizer is also taken into account when calculating the water / solid ratio). Then the foam is discharged onto the surface of the resulting solution, and with stirring, a mixture of gypsum, expanded perlite sand and oxidized dry starch is gradually added. The mixture is mixed with a mixer until a homogeneous mass is obtained, for about 50-60 seconds.

At the third stage, the resulting mixture is unloaded in a pre-prepared form, at the base of which is placed a sheet of backboard. From above, the sample is covered with a sheet of front cardboard and leveled with a special device until a smooth surface is obtained. After curing the solution, the sample is placed in an oven and dried at a temperature of 130 ° C to a moisture content of 0.3% to 0.5%. After drying, the edges of the sample are cut to the size determined by GOST 6266-97. As a result, rectangular samples of the required thickness of 9.5 mm (if necessary 12.5 mm) and a size of 450 mm by 150 mm are obtained. It should be noted that the cardboard was cut out depending on the type of test sample (longitudinal or transverse). For the purity of the experiment, three samples are prepared per test. Assessment of the quality of drywall samples was performed according to GOST 6266-97. The following are examples that illustrate the invention. These examples should not be construed as limiting the scope of the invention, both in terms of components and in the ratio of components.

Example 1

Table 1 presents the composition of the gypsum suspension and the test results of the prepared samples according to GOST 6266-97. All values of the input components in table 1 are indicated in grams (in brackets in% of the weight of the gypsum).

Table 1 Compositions of gypsum slurry and test results of samples with different contents of expanded perlite sand. Component / Parameter
trials Composition 1 Composition 2 Composition 3 Composition 4 Gypsum G6 1000 1000 1000 1000 Sodium lignosulfonate in terms of dry product 5,0 5,0 5,0 5,0

Continuation of the table 1. The composition of the gypsum suspension and the test results of the samples with different contents of expanded perlite sand.

Starch 7 5 7.5 7.5 7.5 oxidized (0.75%) (0.75%) (0.75%) (0.75%) Expanded perlite sand in 3,5 2,5 1,5 1,0 recalculation on a commodity product (0.35%) (0.25%) (0.15%) (0.1%) Foaming agent based on sodium alkyl sulfate and sodium sulfate alkyl ether (active substance concentration 60%) 0.5 0.5 0.5 0.5 Water 570 570 570 570 Spray mm 180 183 183 185 Drying temperature ° С 130 130 130 130 Gluing in accordance with GOST 6266-97 corresponds to corresponds to corresponds to corresponds to Longitudinal load, kgf 24.0 24.1 24.2 24.6 Cross-section load, kgf 8.7 9,4 8.9 8.7 Weight 1 m ² , kg 7.5 7.55 7.6 7.8 Hardness mm 1,5 1,5 1,5 1,5

The results show that the introduction of pre-flooded expanded perlite sand to 0.35% by weight of gypsum leads to a slight decrease in the weight of gypsum plasterboards and only to a slight decrease in the spread of gypsum mixture (composition 1-4).

Additionally, with the introduction of expanded perlite sand, a decrease in brittleness and chips of the samples was observed when fastened with self-tapping screws to the structural profile.

The temperature resistance of the samples was evaluated by comparing the time to failure in a muffle furnace at a temperature of 800 ° C. In this case, the sample with a width of 60 mm and a length of 120 mm was located in the horizontal plane on four point supports located at the corners of the sample. The distance between the supports was 100 mm in length and 40 mm in width. A steel cylinder weighing 400 g and a diameter of 30 mm was placed in the center on top of the sample. For the purity of the experiment, in order to identify the effect of expanded perlite sand on the temperature resistance of the samples, three samples were prepared, with the exception of plasticizer, foaming agent and starch. Sample preparation was carried out in the following order:

The water / gypsum ratio is determined according to GOST 23789-79 (with the introduction of expanded perlite sand, the water / solid ratio is calculated).

Take 300 g of gypsum from G6 and knead the dough of a standard consistency.

The prepared gypsum dough is unloaded into the mold. The result is a rectangular sample measuring 60 mm by 120 mm and 9.5 mm thick.

The following are examples that illustrate the assessment of temperature resistance of samples.

Example 2

Assessment of the resistance of samples to temperature exposure is presented in table 2.

table 2 Assessment of resistance to temperature Component / Parameter
trials Composition 1 Composition 2 Composition 3 Composition 4 Composition 5 Gypsum GB 1000 1000 1000 1000 1000 Expanded perlite sand in 3,5 2,5 1,5 1,0 recalculation on a commodity product (0.35%) (0.25%) (0.15%) (0.1%) 0 Water 571.7 571.4 570.8 570.6 570 Spray mm 180 183 183 185 187 Drying temperature ° С fifty fifty fifty fifty fifty Time to sample destruction, s 390 378 360 360 348

The results obtained show the following:

The introduction of pre-flooded expanded perlite sand into the gypsum core in an amount from 0.1% to 0.35% allows increasing the time of resistance of the samples to temperature exposure up to 10%. In this case, the water / solid ratio in all cases is 0.57, and the spread is within the requirements of GOST 23789-79.

Claims (4)

1. Gypsum composition for drywall sheets with increased resistance to temperature, including: gypsum, dry oxidized starch, technical lignosulfonate, foaming agent, water, characterized in that it further comprises pre-flooded expanded perlite sand in an amount of from 0.1% to 0.35 % by weight of gypsum. 2. The gypsum composition according to claim 1, including expanded perlite sand pre-flooded from 15% to 40%. 3. The gypsum composition according to claim 1, comprising expanded perlite sand with a fraction of 0.16 mm to 1.25 mm. 4. The gypsum composition according to claim 1, comprising a foaming agent based on sodium alkyl sulfate and sodium sulfate alkyl ether.