CEMENTITIOUS COMPOSITION COMPRISING POWDERED POLYURETHANE

Abstract

A cementitious composition, in particular a dry mortar, including a) 5-50 mass parts, preferably 10-45 mass parts, more preferably 15-29 mass parts of a composite hydraulic binder, b) 0.1-4 mass parts, preferably 0.5-3 mass parts, more preferably 1-2 mass parts of powdered polyurethane, and c) optionally 50-90 mass parts, preferably 60-85 mass parts of aggregate. The cementitious composition is particularly useful as a cementitious tile adhesive, a render or part of a render system.

Claims

1. A cementitious composition, wherein it comprises a) 5-50 mass parts of a composite hydraulic binder, b) 0.1-4 mass parts of powdered polyurethane, and c) optionally 50-90 parts of aggregate.

2. A cementitious composition according to claim 1, wherein the composite hydraulic binder comprises a CEM I, CEM II, CEM III, CEM IV, CEM V or CEM VI according to EN 197-1:2018 and at least one supplementary cementing material.

3. A cementitious composition according to claim 1, wherein the composite hydraulic binder is selected from the group consisting of CEM II, CEM III, CEM IV, CEM V or CEM VI according to EN 197-1:2018.

4. A cementitious composition according to claim 2, wherein the supplementary cementing material is chosen from the group consisting of calcined clays, fly ash, silica fume, tuff, trass, pumice, perlite, diatomaceous earth, rice husk ash, burnt shale, limestone, slag, and mixtures thereof.

5. A cementitious composition according to claim 2, wherein the supplementary cementing material is chosen from slag.

6. A cementitious composition according to claim 2, wherein the weight ratio of any of CEM I, CEM II, CEM III, CEM IV, CEM V or CEM VI to supplementary cementing material is in the range of 16:1-1:5.

7. A cementitious composition according to claim 1, wherein it further comprises d) one or more further minerals selected from the group consisting of calcium sulphate, calcium aluminate, high alumina cement, calcium sulphoaluminate cement, and lime.

8. A cementitious composition according to claim 1, wherein the powdered polyurethane material has a particle size in the range of 0.5 μm 8 mm.

9. A cementitious composition according to claim 1, wherein the volume ratio of powdered polyurethane is in a range of from 2-20 Vol-% relative to the total combined volume of powdered polyurethane and aggregate.

10. A processable cementitious composition obtained by mixing a cementitious composition according to claim 1 with water in a water/powder weight ratio between 0.1-0.6.

11. A hardened body obtained by hardening a processable cementitious composition of claim 10.

12. Method for improving the flexibility of a cementitious composition, the method comprising the following steps a) mixing 5-50 mass parts of a composite hydraulic binder, 0.1-4 mass parts of powdered polyurethane, optionally 50-90 mass parts, optionally further minerals, optionally further additives, and water b) applying the mixture obtained in step a) on a support or casting the mixture obtained in step a) into a mold, and c) hardening the mixture to obtain a hardened body.

13. Method for lowering the density of a processable cementitious composition, the method comprising the following steps a) mixing 5-50 mass parts of a composite hydraulic binder, 0.1-4 mass parts of powdered polyurethane, optionally 50-90 mass parts, optionally further minerals, optionally further additives, and b) mixing the mixture obtained in step a) with water in a water/powder ratio between 0.1-0.6.

14. A method comprising making a render or part of a render system using a cementitious composition according to claim 1.

15. A method comprising making a tile adhesive using a cementitious composition according to claim 1.

Description

EXAMPLES

[0101] The following table 1 shows an overview of raw materials used.

TABLE-US-00001 TABLE 1 raw materials used OPC I Ordinary Portland Cement (CEM I 52.5R) OPC II Portland Cement (CEM II 42.5R) GGBFS Ground granulated blast furnace slag (Blaine surface: 4′500 g/cm.sup.2; particle size D50 = 11 μm, (CaO + MgO)/SiO.sub.2 = >1.25) BOFS Basic oxygen furnace slag (primary particle size: 3.5-82 μm, D50 = 22 μm; free lime: 8.5 wt.-%) SF Silica Fume (96% SiO.sub.2, primary particle size: 0.1-0.3 μm) Ca(OH).sub.2 Hydrated lime acc. to standard EN 459-1.2.3 (>93% Ca(OH).sub.2) CaSO.sub.4 Anhydrous calcium sulfate (median particle size 7-10 μm) CaCO.sub.3 Natural ground calcium carbonate (99.1% CaCO.sub.3, particle size D50 = 17 μm; D98 = 125 μm); bulk density: 1400 kg/m.sup.3 Silica Sand Silica sand (particle size 0.063-0.5 mm); bulk density: 1600 kg/m.sup.3 Recycled PU I Ground PU (recyclate from flexible PU foam insulation board; primary particle size: 10-1000 μm; D50 = 250 μm); bulk density: 320 kg/m.sup.3 Recycled PU II Ground PU (recyclate from flexible PU foam insulation board; primary particle size: 0.8-400 μm; D50 = 60 μm) Recycled PU III Ground PU (recyclate from elastic PU adhesive; primary particle size: 10-1000 μm; D50 = 400 μm) Accelerators 1:1 mixture by weight of calcium formiate and sodium chloride Additives I 3:1 mixture by weight of redispersible polymer powder (vinyl acetate- ethylene copolymer; MFFT + 3° C.) and modified cellulose ether Additives II 22:5:1 mixture by weight of redispersible polymer powder (vinyl acetate- acrylic copolymer; MFFT + 7° C.), modified cellulose ether, starch ether

[0102] Test Methods:

[0103] Unless otherwise indicated, hardening was done at 23° C. and 50% r.h.

[0104] Fresh density was measured according to standard EN 1015-6:2007.

[0105] Initial tensile adhesion strength after hardening time as indicated in tables 2 and 3 as well as tensile adhesion strength after 20 min open time were measured in accordance with EN 1346:2008.

[0106] Transverse deformation was measured according to standard EN 12002:2009 after hardening for 28 d.

Example 1

[0107] Example 1 shows the effect of various powdered polyurethane materials in composite binder based cementitious compositions.

[0108] The following table 2 shows reference examples Ref-1 to Ref-3 which are not according to the present invention as well as examples 1-1 to 1-3 which are according to the present invention.

[0109] The compositions of the respective mixes are given in table 1. All numbers refer to a mass in g of the respective material. OPC, GGBFS, CaCO.sub.3, silica sand, and recycled PU and additives were weighed in the respective amounts and mixed in a mixing bowl on a Hobart mixer for 3 min at 23° C./50% r.h. A visually homogeneous dry mix was obtained. Water was added to this dry mix in an amount to yield a weight ratio of water to powder (w/p ratio) as indicated in table 2. Mixing was then continued for another 1.5 min. Measurements were performed as indicated above.

TABLE-US-00002 TABLE 2 effect of various recycled PU Ref-1 Ref-2 Ref-3 1-1 1-2 1-3 OPC II 35 35 21 21 21 21 GGBFS 14 14 14 14 CaCO.sub.3 30 30 30 30 30 30 Silica Sand 33 31.5 33 31.5 31.5 31.5 Recycled PU I 1.5 1.5 Recycled PU II 1.5 Recycled PU III 1.5 Additives 1.9 1.9 1.9 1.9 1.9 1.9 w/p ratio 0.26 0.28 0.26 0.29 0.28 0.26 Fresh density [kg/l] 1.71 1.64 1.69 1.56 1.64 1.58 Initial adhesion 7 d [MPa] n.m. n.m. 0.87 0.68 0.60 0.75 Adhesion open time 20 min n.m. n.m. 0.32 0.27 0.31 0.10 7 d [MPa] Initial adhesion 28 d [MPa] n.m. n.m. 1.13 1 0.9 0.95 Transverse deformation 28 d 1.64 1.23 1.67 1.43 1.35 1.63 [mm] n.m.: not measured

[0110] As can be seen from the above table 2, the addition of powdered PU significantly reduces the fresh density of a given cementitious composition (cf. 1-1 to 1-3 vs Ref-3).

[0111] Adhesion strength results shown in table 2 show that it is possible for a cementitious composition of the present invention to reach to values which are high enough for e.g. a cementitious tile adhesive of type Cl according to EN 12004-1:2017.

[0112] Furthermore, it can be seen from table 2, that the use of powdered polyurethane in a composition based on a composite binder increases the transverse deformation as compared to the use of powdered polyurethane in a composition based on pure OPC (cf. examples 1-1 to 1-3 vs Ref-2).

Example 2

[0113] Example 2 shows the effect of the addition of powdered polyurethane to different composite binders.

[0114] The following table 3 shows reference example Ref-4 which is not according to the present invention as well as examples 2-1 to 2-4 which are according to the present invention.

[0115] The compositions of the respective examples are shown in table 3. All numbers refer to a mass in g of the respective material. The individual compositions were prepared in the same way as example 1 above.

TABLE-US-00003 TABLE 3 effect of powdered PU with various composite binders Ref-4 2-1 2-2 2-3 2-4 OPC I 28 17 9.2 20 25.6 GGBFS 11 8.7 BOFS 9.2 CaSO.sub.4 0.5 Ca(OH).sub.2 7.6 Silica Fume 2 Silica Sand 68 68 68 68 68 Recycled PU I 1.4 1.4 1.4 1.4 1.4 Accelerators 1.6 1.6 1.6 1.6 1.6 Additives 1.5 1.5 1.5 1.5 1.5 Water/powder ratio 0.24 0.24 0.23 0.28 0.25 Fresh density [kg/l] 1.52 1.46 1.44 1.54 1.53 Initial adhesion 7 d [MPa] 1.27 1.01 0.97 0.93 1.25 Adhesion open time 20 min 7 d 0.37 0.49 0.56 0.72 n.m. [MPa] Initial adhesion 28 d [MPa] 1.14 1.03 1.07 1.09 1.11 Transverse deformation 28 d 2.38 2.56 3.12 2.63 2.56 [mm] n.m.: not measured

[0116] As can be seen from the above table 3, adhesion strength values of inventive formulations 2-1 to 2-4 are high enough to comply with requirements for cementitious tile adhesives of type Cl according to EN 12004-1:2017.

[0117] Furthermore, it can be seen from table 3, that the use of powdered polyurethane in compositions based on composite binders strongly increases the transverse deformation as compared to the use of powdered polyurethane in a composition based on pure OPC (cf. examples 2-1 to 2-4 vs Ref-4).

Example 3

[0118] Example 3 shows the effect of the variation of composition of the cementitious composition.

[0119] The following table 4 shows reference example Ref-5 to Ref-7 which are not according to the present invention as well as examples 3-1 to 3-4 which are according to the present invention.

[0120] The compositions of the respective examples are shown in table 4. All numbers refer to a mass in g of the respective material. The individual compositions were prepared in the same way as example 1 above.

TABLE-US-00004 TABLE 4 Effect of variation of composition of the cementitious composition Ref-5 3-1 3-2 3-3 3-4 Ref-6 Ref-7 OPC I 2.4 5.7 32.7 31.3 36 OPC II 28 35 GGBFS 0.6 1.4 8.2 7.8 9.0 CaCO.sub.3 44.7 42.8 27.2 27 25 38 30 Silica Sand 44.7 42.8 27.2 27 25 31.4 31.6 Recycled PU I 3 2.9 1.8 2.7 2 2.5 3 Accelerators 1.64 2.4 1.7 1.5 2.2 Additives II 2.2 2.1 1.4 2.0 1.5 Modified cellulose 0.1 0.4 ether Water/powder ratio 0.32 0.32 0.30 0.34 0.30 0.33 0.36 Fresh density [kg/l] 1.27 1.36 1.56 1.41 1.56 1.69 1.47 Initial adhesion 7 d 0.34 0.52 1.66 1.27 1.58 n.a. 0.77 [MPa] Adhesion open time 0.28 0.44 1.21 1.12 0.64 n.a. 0.36 20 min 7 d [MPa] Initial adhesion 28 d 0.34 0.54 1.26 1.29 1.14 n.a. 0.49 [MPa] Transverse 3.55 3.54 1.71 1.86 1.74 1.14 1.33 deformation 28 d [mm] n.a.: cannot be applied thus cannot be measured