Construction chemical formulation

Abstract

The present invention relates to a quick and low-stress setting chemical formulation for construction, containing at least one binding agent on the basis of calcium sulfate, at least an ettringite-forming agent, at least one activator, at least one filler, at least one redispersable dispersion powder and optionally additives and to the use of the chemical formulation for construction for producing thin-layered balancing masses, self running and solid fillers, screed binding agents or screed mortars, tile adhesive mortars, jointing mortars and sealing sludges.

Claims

1. A construction chemical formulation, comprising a) from 40 to 55 wt. % of at least one binder based on calcium sulfate, which is selected from the group consisting of calcium sulfate -hemihydrate, calcium sulfate -hemihydrate, calcium sulfate anhydrite, calcium sulfate dihydrate and mixtures thereof; b) from 3 to 10 wt. % of at least one ettringite former, which is selected from the group consisting of calcium sulfoaluminate cement, sodium aluminate, high-alumina cement, aluminum sulfate and mixtures thereof; c) from 0.1 to 2 wt. % of at least one activator, which is selected form the group consisting of Portland cement, calcium hydroxide, sodium hydroxide, potassium hydroxide, alkali water glasses and mixtures thereof, wherein the pH is set from 9 to 14 in the construction chemical formulation; d) from 8 to 60 wt. % of at least one filler; and e) from 0.1 to 10 wt. % of at least one redispersible dispersion powder, which is selected from the group consisting of polymers and copolymers of vinyl esters of C.sub.1-C.sub.15 alkyl carboxylic acids, copolymers of vinyl esters of C.sub.1-C.sub.15 alkyl carboxylic acids with olefins or dienes or vinyl halides, and copolymers of ester of (meth)acrylic acid with C.sub.1-C.sub.12 alkanols with styrene; in each case based on the total weight of the construction chemical formulation.

2. The construction chemical formulation according to claim 1, comprising from 46 to 50 wt. % of the binder based on calcium sulfate.

3. The construction chemical formulation according to claim 1, comprising from 41 to 55 wt. % of the binder based on calcium sulfate.

4. The construction chemical formulation according to claim 1, wherein the ettringite former is selected from the group consisting of calcium sulfoaluminate cement, high-alumina cement and mixtures thereof.

5. The construction chemical formulation according to claim 1, comprising 7 wt. % of the ettringite former.

6. The construction chemical formulation according to claim 1, comprising from 3 to 8 wt. % of the ettringite former.

7. A construction chemical formulation, comprising a) from 40 to 55 wt. % of at least one binder based on calcium sulfate, which is selected from the group consisting of calcium sulfate -hemihydrate, calcium sulfate -hemihydrate, calcium sulfate anhydrite, calcium sulfate dihydrate and mixtures thereof; b) from 3 to 10 wt. % of at least one ettringite former, which is selected from the group consisting of calcium sulfoaluminate cement, sodium aluminate, high-alumina cement, aluminum sulfate and mixtures thereof; c) from 0.1 to 2 wt. % of at least one activator, which is selected form the group consisting of Portland cement, calcium hydroxide, sodium hydroxide, potassium hydroxide, alkali water glasses and mixtures thereof, wherein the pH is set from 9 to 14 in the construction chemical formulation; d) from 8 to 60 wt. % of at least one filler; and e) from 0.1 to 10 wt. % of at least one redispersible dispersion powder, which is selected from the group consisting of polymers and copolymers of vinyl esters of C.sub.1-C.sub.15 alkyl carboxylic acids, copolymers of vinyl esters of C.sub.1-C.sub.15 alkyl carboxylic acids with olefins or dienes or vinyl halides, and copolymers of ester of (meth)acrylic acid with C.sub.1-C.sub.12 alkanols with styrene; in each case based on the total weight of the construction chemical formulation, and wherein the amounts of calcium sulfate binder and ettringite former in the total construction chemical formulation is from 43 to 60 wt. %.

8. The construction chemical formulation according to claim 1, wherein the activator is selected from the group consisting of Portland cement, calcium hydroxide and mixtures thereof.

9. The construction chemical formulation according to claim 1, comprising 1 wt. % of the activator.

10. The construction chemical formulation according to claim 1, additionally containing from 0.01 to 7 wt. % of at least one additive, based on the total weight of the construction chemical formulation.

11. The construction chemical formulation according to claim 10, wherein the at least one additive is selected from the group consisting of liquefiers, setting retarders, setting accelerators, thickeners, stabilizers, plastic fibers, dispersants, wetting agents, anti-foaming agents, air-entraining agents and mixtures thereof.

12. The construction chemical formulation according to claim 1, comprising from 0.5 to 10 wt. % of the redispersible dispersion powder.

13. The construction chemical formulation according to claim 1, comprising from 35 to 55 wt. % of the filler.

14. The construction chemical formulation according to claim 1, wherein the filler is selected from the group consisting of silica sands, limestone, limestone powders, dolomite, talc, mica, expanded glass granulates, and expanded clays.

15. The construction chemical formulation according to claim 1, which is substantially free of metakaolin, zeolite or a mixture thereof.

16. A product selected from the group consisting of thin-layer levelling compounds, self-levelling and stable smoothing compounds, screed binders, screed mortars, tile adhesive mortars, grouts and sealing slurries, comprising the construction chemical formulation according to claim 1.

17. A method of levelling or smoothing a floor or subfloor comprising applying to the floor or subfloor the construction chemical formulation according to claim 1.

18. The construction chemical formulation according to claim 1, wherein the pH is set from 11 to 14 in the construction chemical formulation.

Description

(1) The following drawings and examples will be used to explain and illustrate the invention.

(2) FIG. 1 shows peels values after 1, 4, 7, 21 and 28 days when PVC is adhesively bonded to various smoothing compounds (example 1 and comparative examples Comp. 1 to Comp. 4) four hours after application.

(3) FIG. 2 shows peels values after 1, 4, 7, 21 and 28 days when rubber is adhesively bonded to various smoothing compounds (example 1 and comparative examples Comp. 1 and Comp. 4) four hours after application.

(4) FIG. 3 shows peels values after 1 and 4 days when PVC is adhesively bonded to various smoothing compounds (example 1 and comparative examples Comp. 5 to Comp. 8) four hours after application.

(5) FIG. 4 shows peels values after 1 and 4 days when rubber is adhesively bonded to various smoothing compounds (example 1 and comparative examples Comp. 5 to Comp. 8) four hours after application.

EXAMPLES

(6) 1. Formulations

(7) Formulations for smoothing/levelling compounds based on calcium sulfate are given in table 1. Example 1 according to the invention is contrasted with comparative formulations Comp. 1, Comp. 2, Comp. 3 and Comp. 4.

(8) TABLE-US-00001 TABLE 1 Formulations and mixing water requirement for smoothing/levelling compound based on calcium sulfate. Amount [wt. %] Example Comp. Comp. Comp. Comp. Binder system 1 1 2 3 4 Calcium 46 50 50 46 46 sulfate hemihydrate CSA cement 7 10 OPC 1 10 Sand 15 17 17 18 18 Limestone 28.5 30.5 30.5 23.5 23.5 powder Retarder 0.15 0.15 0.15 Dispersion 1.5 1.5 1.5 1.5 1.5 powder Other 0.85 1.0 1.0 0.85 0.85 constituents.sup.1 Mixing water 19 24 19 19 19 requirement [%] based on powder weight .sup.1Additives: Liquefier, thickener

(9) OPC stands for ordinary Portland cement. CS10 from the company Belith was used as the CSA cement. The sand had an average particle size of from 0.01 to 10 mm and a quartz content of more than 99%. Limestone powder is to be understood to mean natural, pulverised calcium carbonate having a particle size of less than 500 m. An ethylene-vinyl acetate copolymer having an MFFT of 4 C. was used as the dispersion powder. Tartaric acid was used as the retarder.

(10) 2. Assessing the Readiness for Covering

(11) The readiness for covering of a subfloor corresponds to the period between application of the levelling/smoothing compound and the time from which functional adhesive bonding of floor coverings is possible. In general, peel values of greater than 0.6 N/mm after 24 hours are required for functional, defect-free adhesive bonding. These values should also increase continuously and preferably be at least 1 N/mm (after approximately 4-7 days).

(12) In order to assess the readiness for covering, the smoothing/levelling compounds were applied to a layer thickness of 2.5 mm. A dry concrete subfloor pretreated with a sealing one-component rapid primer (UZIN PE 414 Turbo) and a dispersion-based adhesion promoter (Uzin PE 280) was selected as the subfloor.

(13) The adhesive bonding of vapour-tight floor coverings took place four hours after the smoothing/levelling compound was applied. A dispersion-based universal adhesive (UZIN KE 2000 S) was used to adhesively bond PVC (Armstrong DLW Royal). Rubber coverings (Nora Noraplan Mega) were adhesively bonded using a wet-bed dispersion adhesive (e.g. UZIN KE 66). Subsequently, at various times after the adhesive bonding, strips (width: 5 cm) were peeled off the subfloor using a spring balance, and thus the peel values (in N/mm) were determined.

(14) When a PVC covering was adhesively bonded to a conventional smoothing/levelling compound based on calcium sulfate (Comp. 1) four hours after application, a maximum peel value of approximately only 0.4 N/mm (cf. FIG. 1) was displayed even 28 days after adhesive bonding. This value is not sufficient for lasting functional adhesive bonding. The extremely low peel values 24 hours or seven days after adhesive bonding gave a further indication that a product of this kind is not ready for covering four hours after application. This is even more considerable when rubber coverings are adhesively bonded (cf. FIG. 2). In this case, barely measurable peel values (<0.4 N/mm) were reached even after 28 days.

(15) Comparative example Comp. 2 differs from the conventional smoothing/levelling compound based on calcium sulfate Comp. 1 on account of a reduced mixing water requirement. This accelerated the drying process. This was apparent from the slightly higher peel values after adhesive bonding of PVC. The peel values of greater than 0.6 N/mm after 24 hours required for functional, defect-free adhesive bonding were not reached for the comparative example.

(16) Comparative examples Comp. 3 and Comp. 4 demonstrate that it was only possible to achieve a readiness for covering of four hours after application by using the binder system (example 1) according to the invention. The addition of Portland cement (Comp. 3) and the associated increase in pH in the system did not result in any significant improvement in the peel values (FIG. 1). On account of the inadequate concentration of Al.sup.3+ or Al(OH).sub.3, it was not possible for enough ettringite to be formed in order to bind surplus water.

(17) The combination of a calcium sulfate binder with calcium sulfoaluminate cement (Comp. 4), in the absence of Portland cement, resulted no more so in readiness for covering after four hours.

(18) The smoothing compound according to the invention (example 1) displayed significantly higher peel values (FIGS. 1 and 2) than the comparative example products both when PVC was adhesively bonded and when rubber was adhesively bonded. By combining calcium sulfate hemihydrate with calcium sulfoaluminate cement and Portland cement in order to set the pH 9, it was possible to achieve faster drying of the smoothing compound. It was possible to bind almost all surplus water in the ettringite crystals that form and it was not necessary to discharge said water to the environment. This quickly reduced the residual moisture in the smoothing compound, and therefore water that was introduced by the adhesive could be compensated for.

(19) This made functional adhesive bonding possible as early as four hours after application of the smoothing compound. Sufficiently high peel values were reached as early as 24 hours after adhesive bonding, and said values increased further with time. Peel values of >1 N/mm were reached as early as approximately four days after the adhesive bonding both when PVC was adhesively bonded and when rubber was adhesively bonded.

(20) In a further experiment, the formulation of example 1 and further comparative formulations were produced and tested according to the above-described methods. The above-described PVC and rubber coverings were used as the floor covering. The comparative formulations represent the binder compositions described in WO 2014/108435 and WO 2014/108436. The compositions of the tested formulations are collated in table 2; the results are shown graphically in FIGS. 3 and 4.

(21) TABLE-US-00002 TABLE 2 Example Comp. Comp. Comp. Comp. 1 5 6 7 8 Component Amount [wt. %] Calcium 46 40 40 40 35.5 sulfate hemihydrate CSA cement 7 High-alumina 5 5 5 3.5 cement OPC 1 8 8 8 6.5 Metakaolin 5 2.5 2.25 Zeolite 5 2.5 2.25 Sand 15 19.15 19.15 19.15 49.95 Limestone 28.5 20 20 20 powder Retarder 0.15 0.05 0.05 0.05 Dispersion 1.5 2.5 2.5 2.5 powder Other 0.85 0.3 0.3 0.3 0.05 constituents.sup.1 Mixing water 19 20 20 20 25 requirement [%] based on powder weight .sup.1Additives: Liquefier, thickener

(22) It can be seen from FIGS. 3 and 4 that, when the formulation according to the invention is used, readiness for covering (peel value 0.6 N/mm.sup.2) is reached after one day both when PVC floor coverings are adhesively bonded and when rubber floor coverings are adhesively bonded. However, when the formulations according to the prior art are used, readiness for covering is only reached after four days when PVC coverings are adhesively bonded, and is not reached, even after four days, when rubber coverings are adhesively bonded.