DE2557594B2 - Self-leveling building material based on calcium sulfate a-hemihydrate - Google Patents

Description

6. Building materials according to claim 5, characterized in that the surfactant mixture consists of

11.5% by weight Ci ₂ - Cn ether sulfate
10% by weight of the sodium salt of

Oleic acid N-methyl tauride

6% by weight of C _{) 6} - de-olefin sulfonate
25% by weight butyl diglycol and

47.5% by weight water
consists.

7. Building material according to one of claims 1 to 6, characterized in that it is additionally 0.01 to 2% by weight of alkylene oxide high polymers, based on the calcium sulfate tx hemihydrate

8. Building material according to one of claims 1 to 6, characterized in that it is additionally 0.01 to 2% by weight of cellulose ether based on the calcium sulfate ac hemihydrate contains

9. Building material according to claim 8, characterized in that the cellulose ether is carboxymethyl cellulose is included.

10. Building material composition according to claim 8, characterized in that the cellulose ether is methyl cellulose is included.

The invention relates to a self-leveling building material based on calcium sulfate a-hemihydrate with a content of surfactants.

Laying a useful floor, for example from

Tile or wooden parquet, is only on a horizontal and even surface, but not on the mostly uneven and rough ceilings of buildings possible.

While earlier, to produce the necessary horizontal and even surfaces, screeds were made Mastic asphalt, cement or magnesite were used, their application, leveling and smoothing one Bring considerable work with it, mortar mixtures have been known for some time, which have a flowable and punchable consistency after the addition of water and under the influence of the

is gravity like a liquid leveling itself and smooth.

For example, from DE-OS 1943 634 a mortar mass is known which consists of anhydrite and sand and a die Sedimentation of the solids in water retards and the strength of the hardening mass increasing substance, the first substance can be a cellulose ether, while the second Substance a sulfite or sulfonic acid modified resin This mixture is based on an amino-s-triazine with at least two NH2 groups processed with water in a weight ratio of up to 2: 1 to a flowable mass and placed on a load-bearing Underlay is poured out, where it flows apart to form a horizontal surface and into frozen in this state

The disadvantage of this mortar mass is that it sets very slowly with water, so that bad Early strengths result. In addition, in the interests of good flowability of the mixture, the Sand content can be kept low, whereby however a considerable addition of the strength of the hardening Weight-increasing modified resin based on an amino-s-triazine, which is relatively expensive, is required.

To counteract the disadvantage of slow setting of the anhydrite-based mortar mass, a building material composition is described in DE-OS 23 59 290, which consists of calcium sulfate - /? - hemihydrate Alumina cement and / or Portland cement, the above-mentioned modified resin based on Amino-s-triazine as a strength-increasing substance as well as a setting retarder and / or a filler This building material is mixed with water in the amount required for flowability

This amount of water is relatively large, since calcium sulfate-j3 hemihydrate alone is necessary for the complete setting as well as the cement contained in the building material, a lot of water is required As a result, on the one hand, the construction progress hindering long drying times are required while on the other hand, when the excess water in the set building material evaporates, a large one Pore volume is created, as a result of which the final strength of the mass is reduced.

The screed compound for floors according to DE-OS 22 47 756 consists of a mixture of calcium sulfate a-hemihydrate, white lime, a liquefier, for example water-soluble high-molecular aminoplasts or polysilicic acids, and a setting retarder, the same amount of building sand being added to the mixture This screed mass can be poured with water and subsequent stirring.
The disadvantage of this screed compound is its low level

Fluidity so that they are alone under the influence gravity does not level and smooth itself before it solidifies

The porous material according to the US-PS suitable as sound-absorbing plaster for walls and ceilings 18 48 386 consists of a binding agent, for example calcium sulphate a-hemihydrate with a setting retarder, and an aggregate such as sand or slag. The proportion by weight of binder must be used be significantly smaller than the weight fraction of aggregate, so that the particles of the aggregate at their Points of contact are glued together by the binder, the gaps between the particles of the However, the aggregate remains free. A firmer product is obtained when you mix the mixture Binder, aggregate and water a surface tension-reducing agent, for example Sodium benzene sulfonate, which adds this makes the water more responsive to capillarity, creating a larger amount of binder is brought to the contact surfaces of the particles of the aggregate.

Finally, from GB-PS 1390360 a self-leveling mortar composition is known, which consists of calcium sulphate a-hemihydrate, less than 35% by weight of water and at least 10% by weight a solid synthetic resin. The mortar composition can be 0 to 2% by weight Antifoam agents, for example chemically modified natural oils or fats as well as dispersed in light oil Mixtures of synthetic or natural esters or metallic soaps.

The disadvantage of this mortar is that on the one hand its flowability leaves something to be desired and on the other hand its times for stiffening start and stiffening end are very short. In addition, this mortar must are stored separately in two partial mixes, which are to be mixed in the correct weight ratio on the construction site immediately before processing.

Furthermore, in the unpublished DE-OS 26 31 031 a flowable gypsum mass is proposed, which calcium sulfate with a content of at least about 50% by weight calcium sulfate a-hemihydrate and contains a surface-active phosphoric acid ester. The flowable plaster of paris still contains a Sulfonic acid type dispersant and also an alkali metal sulfate

It is therefore the object of the present invention to provide a building material based on calcium sulfate a-hemihydrate with a content of surface-active substances Specify materials which do not have the disadvantages mentioned. Such a building material must rather be mixable with relatively little water to a material with good flowability on the one hand to ensure short drying times and on the other hand under the influence of gravity self-leveling and smoothing, with the addition of Lean agents such as sand, slag or solid synthetic resin in the interests of good flowability and the addition of expensive substances to increase the final strength must be dispensed with. Furthermore the building material must have a favorable time behavior with regard to the beginning and end of its stiffening.

This is achieved according to the invention in that a surface-active substance is used as a surface-active substance in the building material Surfactant mixture and at least one phosphoric acid ester are included.

The building material composition according to the invention can optionally also be characterized in that

a) they are 0.1 to 2% by weight, preferably 0.3 to 0.7 % By weight, phosphoric acid ester, based on the calcium sulfate a-hemihydrate;

b) they are mono-, di- or tri-alkyl esters with 3 to 10 carbon atoms, preferably as phosphoric acid esters with 4 to 6 carbon atoms, or mixtures thereof;

c) it is 0.1 to 2% by weight, preferably 0.3 to 0.7 % By weight, surfactant mixture, based on the

ι ο calcium sulfate a hemihydrate, contains;

d) the surfactant mixture of 5 to 40% by weight of an alkyl ether sulfate with 10 to 18 carbon atoms, 5 to 15 % By weight of an alkali salt of oleic acid-N-methyl tauride, 5 to 30% by weight of an olefin sulfo-

nates with 10 to 18 carbon atoms, 10 to 40% by weight of a diglycol with 2 to 6 carbon atoms and the remainder is water;

e) the surfactant mixture of 11.5% by weight Ci ₂ -Cu ether sulfate, 10% by weight of the sodium salt of Oleic acid-N-methyltauride, 6% by weight Ci ₆ -Cw-Oiefinsulfonat, 25% by weight butyl diglycol and 47.5% by weight water;

f) they additionally 0.01 to 2% by weight of alkylene oxide high polymers, based on the calcium sulfate-a-

Hemihydrate, contains;

g) it additionally contains 0.01 to 2% by weight of cellulose ether, based on the calcium sulfate a-hemihydrate;

h) the cellulose ether contains carboxymethyl cellulose;

i) the cellulose ether contains methyl cellulose.

A flowable material can be produced from the building material composition according to the invention in that the building material and water in a weight ratio of 3.0 to 3.7 to 1 intimately with one another mixed

Calcium sulphate a-hemihydrate should be one that determines a water gypsum value (

■ ίο according to DIN 1168, part 2, page 3, July 1975 edition) of 0.37 to 0.50, preferably 0.40 to 0.43. The commercially available hard plaster meets this condition as well as a according to DE-PS 1157182 in aqueous solution Calcium sulfate a hemihydrate produced according to Abfil trimming, drying and grinding to a grain size <100 μm.

All additives according to the invention can, although they are partially liquids, with the help of suitable Mixing units homogeneous in calcium sulphate-a-half-hy drat to be distributed. The building material according to the invention The mass is sufficiently stable in storage so that only the required amount of water is left on the construction site must be measured and added. If the building material composition according to the invention with Water, for example, in a weight ratio of 3.5: 1 mixed, a flowable material is obtained which, after pouring, becomes like a liquid spreads, so that an expensive leveling and smoothing by hand or by aids is dispensable After the flowable material has set, with this ratio of building material mass to water only about 5 to 7% water can be evaporated to the usual residual moisture of about 3 to with laid screed Reach 5%.

With the building material according to the invention, a flowable material can be produced whose setting behavior is almost ideal At the beginning of the stiffening, sufficient processing

time, while the relatively short stiffening end that follows avoids unnecessary waiting times. The delayed start of stiffening occurs, although the building material composition according to the invention does not Contains setting retarders, which apart from Their additional costs, reduce the strength of the hardened screed and are often the cause of unwanted efflorescence.

Floor coverings produced with the building material according to the invention have such a high early strength that they can be walked on even a short time after pouring. After a few days, the floor coverings show compressive strengths of more than 300 kp / cm ² and bending tensile strengths of more than 80 kg / cm ² and are thus above the values required in DIN 4109 (cf. sheet 4, page 3, edition 1962) for un-skimmed gypsum screeds.

The invention will now be explained on the basis of examples

example 1

apart, levels itself and hardens after about an hour, forming a smooth, pore-free surface. The area can be walked on after 3 hours. After 4 to 5 days, the surface has a compressive or flexural strength of 326 and 108 kp / cm ^2, respectively.

Example 3

50 kg of a commercially available hard plaster of paris from natural plaster with a water plaster of paris value of 0.42 are intimately mixed with 250 g of tri-isobutyl phosphate and 250 g of a surfactant mixture, a homogeneous and lump-free mass with good storage stability results

The surfactant mixture used consists of:

20th

35

50 kg of a commercially available hard plaster cast from natural plaster with a water plaster of paris value of 0.42 are with 200 g of tri-iso-butyl phosphate, 200 g of a surfactant mixture and 100 g of a high polymer the base of alkylene oxide intimately mixed, resulting in a homogeneous and lump-free mass with good storage stability results.

The surfactant mixture used consists of:

11.5% by weight Ci ₂ -C _M ether sulfate

10% by weight of the sodium salt of

Oleic acid N-methyl tauride
6% by weight Ci ₆ - C | _g -olefin sulfonate
25% by weight butyl diglycol
47.5% by weight water.

The homogeneous mass is mixed with water in a weight ratio of 3.7: 1, a suspension with excellent flow behavior results.

To illustrate the flow behavior, the suspension is left out of a Vicatring, which is on a The spreading table lies, flow out (cf. the determination of the slump according to DIN 1168, Part 2, Pages 3 and 4, July 1975 edition). The slump is 40 cm.

The suspension begins to stiffen at around 60 minutes.

The compressive and flexural strengths measured on test specimens in accordance with DIN 1168 are 316 and 86 kp / cm ^2, respectively.

50

Example 2

Gypsum obtained as a by-product in the production of wet phosphoric acid is according to DE-PS

11 57 128 converted to calcium sulfate a hemihydrate and after filtering off and drying, ground to a grain size of <100 μm.

150 kg of this calcium sulfate a-hemihydrate with a water gypsum value of 0.40 with 750 g of tri-n-butyl phosphate, 750 g of that used in Example 1 Surfactant mixture and 115 g of a methyl cellulose, the 2% aqueous solution of which has a medium viscosity of about 1000 cP, intimately mixed

100 kg of this mixture are mixed with 28.61 of water mixed, and the flowable material is transferred to a Load-bearing base conveyed The material flows under in a divided area element of 1 χ 2 m Formation of an approximately 3 cm thick layer independently 6% by weight

27.5% by weight

5% by weight

7.5% by weight
12.5% by weight
41.5% by weight

Ci2-Ci4 ether sulfate
Cm — Ci2 ether sulfate
of the sodium salt of
Oleic acid N-methyl tauride
C16 - C] g olefin sulfonate
Butyl diglycol
Water.

The homogeneous mass is mixed with water in a weight ratio of 3.6: 1, a suspension with excellent flow behavior results

To illustrate the flow behavior, the suspension is left out of a Vicatring, which is on a Spreading table lies, flow out (see DIN 1168). That Slump is 38 cm.

The suspension begins to stiffen at around 70 minutes.

The compressive and flexural strengths measured on test specimens in accordance with DIN 1168 are 304 and 82 kp / cm ^2, respectively.

Example 4

Gypsum obtained as a by-product in the production of wet phosphoric acid is according to DE-PS 11 57 128 converted to calcium sulfate a hemihydrate and after filtering off and drying, ground to a grain size of <100 μm.

2 kg of this calcium sulfate a-hemihydrate with a water gypsum value of 0.40 with 12 g of a equimolar mixture of mono- and dihexyl phosphoric acid ester, 10 g of that used in Example 1 Surfactant mixture and 2 g of a methyl cellulose, the 2% aqueous solution of which has an average viscosity of has about 1000 cP intimately mixed

This mixture is stirred with 570 ml of water. If part of the suspension is allowed to flow out of a Vicat ring as indicated in Example 1, the slump is 36 cm. The compressive and flexural strengths measured on test specimens in accordance with DIN 1168 are 310 and 85 kp / cm ^2, respectively.

Example 5

In the production of sodium phosphoric acid as a by-product of gypsum, according to DE-PS 11 57 128 converted to calcium sulfate iX hemihydrate and after filtering off and drying, ground to a grain size of <100 μm.

2 kg of this calcium sulfate a-hemihydrate with a Water gypsum value of 0.45 is used with 14 g of dibutylphosphoric acid ester, 12 g of that used in Example 3 Surfactant mixture and 1.5 g of a methyl cellulose, the 2% aqueous solution of which has an average viscosity of about 1000 cP has this mixture intimately mixed

is stirred with 600 ml of water. If part of the suspension is allowed to flow out of a Vicat ring as indicated in Example 1, the slump is 38 cm. The pressure or pressure measured on test specimens according to DIN 1168 Flexural strengths are 302 and 81 kp / cm ^2, respectively.

Example 6

Gypsum obtained as a by-product in the production of wet phosphoric acid is according to DE-PS 11 57 128 converted to calcium sulfate hemihydrate and no after filtering off and drying, ground to a grain size of <100 μm.

2 kg of this calcium sulfate a-hemihydrate with a

Water gypsum value of 0.45 is mixed with 10 g of tris (3-phenylpropyl) phosphate, 10 g of the surfactant mixture used in Example 3 and 1.5 g of a methyl cellulose, whose 2% aqueous solution has an average viscosity of about 1000 cP, intimately mixed.

This mixture is mixed with 590 ml of water. If part of the suspension is allowed to flow out of a Vicat ring as indicated in Example 1, the slump is 34 cm. The compressive and flexural strengths measured on test specimens in accordance with DIN 1168 are 308 and 85 kp / cm ² . The start of stiffening is 48 minutes, the end of stiffening is 100 minutes.

Claims (5)

Patent claims: 1. Self-leveling building material based on calcium sulfate-a-hemihydrate with a content of surface-active substances, characterized in that as surface-active Substances a surfactant mixture and at least one phosphoric acid ester are included. 2. Building material mass according to claim 1, characterized in that it is 0.1 to 2% by weight, preferably 0.3 to 0.7% by weight, phosphoric acid ester, based on the calcium sulfate a-hemihydrate, contains 3. Building material according to claim 1 or 2, characterized in that it is used as a phosphoric acid ester Mono-, di- or tri-alkyl esters with 3 to 10 Contains carbon atoms, preferably with 4 to 6 carbon atoms, or mixtures thereof 4. Building material according to one of claims 1 to 3, characterized in that it contains 0.1 to 2% by weight, preferably 0.3 to 0.7% by weight, Surfactant mixture, based on the calcium sulphate - «- hemihydrate contains 5. Building material according to one of claims 1 to 4, characterized in that the surfactant mixture from 5 to 40% by weight of an alkyl ether sulfate
with 10 to 18 carbon atoms, 5 to 15% by weight of an alkali salt of the Oleic acid N-methyl tauride, 5 to 30% by weight of an olefin sulfonate with 10 to 18 carbon atoms,
10 to 40% by weight of a diglycol with 2 to 6 carbon atoms and
Rest water
consists