Rapidly suspendable pulverulent composition

Abstract

The invention relates to a pulverulent composition comprising, based on the overall mass of the composition, A) at least 20 wt % of a calcium sulfate-based binder and B) 0.01 to 4 wt % of at least one copolymer obtainable by polymerizing a mixture of monomers comprising (I) at least one ethylenically unsaturated monomer which comprises at least one radical from the series carboxylic acid, carboxylic salt, carboxylic ester, carboxylic amide, carboxylic anhydride, and carboxylic imide and (II) at least one ethylenically unsaturated monomer having a polyalkylene oxide radical, the pulverulent composition being producible by a method in which a powder component comprising a calcium sulfate-based binder is contacted with a liquid hydrous component comprising less than 30 wt % of an organic solvent, comprising B), the liquid hydrous component being used in an amount of less than 20 wt %, based on the overall mass of the pulverulent composition, and the pulverulent composition comprising no hydraulic binder. A binder composition comprising an inventive pulverulent composition is also disclosed.

Claims

1. A pulverulent composition comprising, based on the overall mass of the composition: A) at least 20 wt % of a calcium sulfate-based binder and B) 0.01 to 4 wt % of at least one copolymer at least partially coating the binder, the copolymer obtained by a process comprising polymerizing a mixture of monomers comprising (I) at least one ethylenically unsaturated monomer which comprises at least one radical from the series carboxylic acid, carboxylic salt, carboxylic ester, carboxylic amide, carboxylic anhydride, and carboxylic imide and (II) at least one ethylenically unsaturated monomer having a polyalkylene oxide radical, wherein the pulverulent composition is produced by contacting a powder component comprising a calcium sulfate-based binder with a liquid hydrous component comprising less than 30 wt % of an organic solvent comprising B), wherein the liquid hydrous component is added in an amount of less than 20 wt %, based on the overall mass of the pulverulent composition, and wherein the pulverulent composition contains no hydraulic binder.

2. The pulverulent composition according to claim 1, wherein the calcium sulfate-based binder of the powder component comprises anhydrite and/or -calcium sulfate hemihydrate.

3. The pulverulent composition according to claim 1, wherein the method, after the addition of the liquid hydrous component, comprises no physical drying step.

4. The pulverulent composition according to claim 1, wherein the ethylenically unsaturated monomer (I) is represented by at least one of the following general formulae from the group (Ia), (Ib), and (Ic) ##STR00009## where R.sup.1 and R.sup.2 independently of one another are hydrogen or an aliphatic hydrocarbon radical having 1 to 20 C atoms, Y is H, COOM.sub.a, COO(C.sub.qH.sub.2qO).sub.rR.sup.3, or CONH(C.sub.qH.sub.2qO).sub.rR.sup.3, M is hydrogen, a mono- or divalent metal cation, ammonium ion, or an organic amine radical, a is or1, R.sup.3 is hydrogen, an aliphatic hydrocarbon radical having 1 to 20 C atoms, a cycloaliphatic hydrocarbon radical having 5 to 8 C atoms, or an optionally substituted aryl radical having 6 to 14 C atoms, q independently at each occurrence for each (C.sub.qH2.sub.qO) unit is identical or different and is 2, 3, or 4, r is 0 to 200, and Z is O or NR.sup.3, ##STR00010## wherein R.sup.4 and R.sup.5 independently of one another are hydrogen or an aliphatic hydrocarbon radical having 1 to 20 C atoms, a cycloaliphatic hydrocarbon radical having 5 to 8 C atoms, or an optionally substituted aryl radical having 6 to 14 C atoms, Q is identical or different and is represented by NH, NR.sup.3, or O, where R.sup.3 possesses the definition stated above, R.sup.6 is identical or different and is represented by (C.sub.nH.sub.2n)SO.sub.3H with n =0, 1, 2, 3, or 4, (C.sub.nH.sub.2n)OH with n =0, 1, 2, 3, or 4; (C.sub.nH.sub.2n)PO.sub.3H.sub.2 with n =0, 1, 2, 3, or 4, (C.sub.nH.sub.2n)OPO.sub.3H.sub.2 with n=0, 1, 2, 3, or 4, (C.sub.6H.sub.4)SO.sub.3H, (C.sub.6H.sub.4)PO.sub.3H.sub.2, (C.sub.6H.sub.4)OPO.sub.3H.sub.2, and (C.sub.nH.sub.2n)NR.sup.8.sub.b with n =0, 1, 2, 3, or 4 and b =2 or 3, R.sup.7 is H, COOM.sub.a, COO(C.sub.qH.sub.2qO).sub.rR.sup.3, CONH(C.sub.qH.sub.2qO).sub.rR.sup.3, wherein M.sub.a, R.sup.3, q, and r possess definitions stated above, R.sup.8 is hydrogen, an aliphatic hydrocarbon radical having 1 to 10 C atoms, a cycloaliphatic hydrocarbon radical having 5 to 8 C atoms, or an optionally substituted aryl radical having 6 to 14 C atoms.

5. The pulverulent composition according to claim 1, wherein the ethylenically unsaturated monomer (II) is represented by the following general formula ##STR00011## wherein p is an integer between 0 and 6, y is 0 or 1, v is an integer between 3 and 500, w independently at each occurrence for each (C.sub.wH.sub.2wO) unit is identical or different and is an integer between 2 and 18, T is oxygen or a chemical bond, R.sup.1 and R.sup.2 independently of one another are hydrogen or an aliphatic hydrocarbon radical having 1 to 20 C atoms, and R.sup.3 is hydrogen, an aliphatic hydrocarbon radical having 1 to 20 C atoms, a cycloaliphatic hydrocarbon radical having 5 to 8 C atoms, or an optionally substituted aryl radical having 6 to 14 C atoms.

6. The pulverulent composition according to claim 1, wherein the fraction of the monomer (I) in the copolymer is 5 to 95 mol %.

7. The pulverulent composition according to claim 1, wherein the fraction of the monomer (II) in the copolymer is 1 to 89 mol %.

8. The pulverulent composition according to claim 1, wherein the pulverulent composition, based on the overall mass of the composition, comprises between 85 and 99.99 wt % of the calcium sulfate-based binder.

9. The pulverulent composition according to claim 1, wherein the liquid hydrous component is contacted with the powder component by spraying on or atomizing.

10. The pulverulent composition according to claim 1, wherein the powder component is subjected to a mixing operation during and/or after the contacting with the liquid hydrous component to ensure homogeneous application.

11. A gypsum plasterboard, screed, static or self-leveling filling compound, plaster, render or modelling material comprising as a binder the pulverulent composition of claim 1.

12. A binder composition comprising a pulverulent composition according to claim 1 and at least one further binder selected from the group consisting of cement based on Portland cement, white cement, calcium aluminate cement, calcium sulfoaluminate cement, and latent hydraulic and pozzolanic binder.

13. A binder composition comprising a pulverulent composition according to claim 12, wherein the binder composition is a factory dry-mix mortar.

14. A method comprising preparing a liquid hydrous component, wherein the liquid hydrous component comprises less than 30 wt % of an organic solvent and a copolymer obtained by polymerizing a mixture of monomers, wherein the mixture of monomers comprises (I) at least one ethylenically unsaturated monomer which comprises at least one radical from the series carboxylic acid, carboxylic salt, carboxylic ester, carboxylic amide, carboxylic anhydride, and carboxylic imide and (II) at least one ethylenically unsaturated monomer having a polyalkylene ether radical, and spraying or atomizing onto a powder component comprising a calcium sulfate-based binder, thereby obtaining a calcium sulfate-based binder at least partially coated with the copolymer, suitable for accelerating the homogeneous dispersing of the product with water, and wherein the powder component contains no hydraulic binder.

15. The composition of claim 1, having a slump that is at least 9% greater than a slump of an otherwise-identical composition that instead comprises the copolymer as a separate component in aqueous solution.

16. The composition of claim 1, having a slump that is at least 10% greater than a slump of an otherwise-identical composition that instead comprises the copolymer as a separate dry component.

Description

EXAMPLES

(1) Composition of the Inventive Copolymer

(2) The synthesis of the copolymer used is described for example in WO2006133933 page 12, line 5 to page 13, line 26. The composition of the copolymer used is as follows:

(3) TABLE-US-00001 Copolymer 1 Mol of acrylic Mol of Macro- Mw Solids acid macromonomer monomer (g/mol) % 5 1 VOBPEG-3000 32 000 50 The abbreviation VOBPEG-3000 stands for vinyloxybutyl-polyethylene glycol with a molar mass of 3000 g/mol.
Determination of Slump

(4) Production of inventive pulverulent composition:

(5) 1 kg of calcium sulfate -hemihydrate (-HH) is charged to a forced mixer. While the material is mixed at 950 revolutions per minute (rpm), 20 g of a 50 wt % strength aqueous solution of copolymer 1 (active ingredient content: 0.1% based on -HH) are sprayed on at room temperature over the course of 25 seconds. This is followed by mixing for a further 90 seconds. After a short break in mixing, of a few seconds, the mixture is stirred again for a further 120 seconds.

Inventive Example 1

(6) Use of the inventive pulverulent composition as binder in a gypsum slurry (calcium sulfate paste).

Inventive Example 2

(7) Use of the inventive pulverulent composition as binder in a blend with finely ground limestone (Omyacarb 130 AL) in a ratio of 1:1.

Comparative Example 1

(8) Use of untreated -HH as binder in a gypsum slurry (for determining the blank value based on the mixture of water and -HH without plasticizer).

Comparative Example 2

(9) Gypsum slurry, based on untreated -HH, where the abovementioned 50 wt % strength aqueous solution of copolymer 1 is added to the mixing water.

Comparative Example 3

(10) Gypsum slurry, based on untreated -HH, where copolymer 1 is added as a powder to the -HH.

Comparative Example 4

(11) Use of untreated -HH as binder in a blend with finely ground limestone (Omyacarb 130 AL) in a ratio of 1:1 (for determining the blank value of the blend of untreated -HH with finely ground limestone, without plasticizer).

Comparative Example 5

(12) Blend of untreated -HH with finely ground limestone (Omyacarb 130 AL) in a ratio of 1:1, where the abovementioned 50 wt % strength aqueous solution of copolymer 1 is added to the mixing water.

Comparative Example 6

(13) Blend of untreated -HH with finely ground limestone (Omyacarb 130 AL) in a ratio of 1:1, where copolymer 1 is added as a powder to the dry component.

Application Examples

(14) Investigation of the flow behaviour of the inventive pulverulent composition as pure gypsum slurry or as blend of the inventive pulverulent composition with finely ground limestone (Omyacarb 130AL type).

General Application Example 1

(15) The gypsum slurries are produced using in each case 300 g of -HH. The quantity of water needed, corresponding to a water-to-binder (w/g) ratio of 0.59 and determined on the basis of the untreated gypsum slurry (comparative example 1), is charged to a mixing vessel (mixer according to DIN EN 196-1) and then the -HH is sprinkled carefully into the water. In the case of inventive example 1, the -HH already contains the required amount of plasticizer of 0.1 wt % (copolymer 1); in the case of comparative examples 2) and 3), copolymer 1 is added separately in liquid form in the mixing water or as powder, likewise giving an active ingredient concentration of 0.1 wt %, based on the -HH employed. In addition, all mixtures contain 0.08 wt % of Retardan P, based on the amount of -HH used. Stirring takes place for 15 seconds on setting 1 and then for 15 seconds more on setting 2.

(16) To determine the flow behaviour, the mixtures are introduced into a cone (internal diameter of 5 cm and height of 10 cm), and after a period (including mixing operation) of 60 seconds, the slump is determined.

(17) The results of the application tests for inventive example 1 and comparative examples 1 to 3 are set out in table 1 below:

(18) TABLE-US-00002 TABLE 1 Investigation of the flow behaviour in a gypsum slurry Gypsum Gypsum slurry + slurry + Gypsum 0.1 wt % 0.1 wt % slurry copolymer 1 copolymer 1 inventive Blank value as powder solution -HH (comparative (comparative (comparative (inventive example 1) example 3) example 2) example 1) -HH (g) 300 300 300 300 wt % 0 0.1 0.1 0.1 plasticizer based on -HH w/g 0.59 0.59 0.59 0.59 slump (cm) 14.8 19.3 21 25.9 Inventive example 1, comprising the inventive pulverulent composition, displays a marked increase in the slump, of 75% relative to the blank value and of 23% and 34% relative to the use of the plasticizer in the mixing water and as powder, respectively.

Application Example 2

(19) 500 g in each case, consisting of a 1:1 blend of -HH with finely ground limestone, are charged to the mixing vessel of a forced mixer. Stirring takes place at 950 rpm for 60 seconds, with the amount of water required, corresponding to a w/g of 0.87 and determined on the basis of the mixture without plasticizer (comparative example 4), being added after 5-10 seconds. In the case of inventive example 2, the blend already contains the required amount of plasticizer of 0.1 wt % (copolymer 1), based on -HH.

(20) In the case of comparative examples 5) and 6), copolymer 1 is added separately in liquid form in the mixing water or as powder, likewise in an active ingredient concentration of 0.1 wt %, based on -HH. In addition, all mixtures contain 0.08 wt % of Retardan P, based on the amount of -HH used.

(21) To determine the flow behaviour, the mixtures are introduced into a cone (internal diameter of 5 cm and height of 10 cm), and after a period (including mixing operation) of 120 seconds, the slump is determined. The results of the application tests for inventive example 2 and comparative examples 4 to 6 are set out in table 2 below:

(22) TABLE-US-00003 TABLE 2 Investigation of the flow behaviour of a 1:1 blend of -HH with finely ground limestone Mixture + 0.1 Mixture + 0.1 wt % wt % Mixture copolymer copolymer inventive Blank value 1 as powder 1 solution -HH (comparative (comparative (comparative (inventive example 4) example 6) example 5) example 2) -HH (g) 250 250 250 250 finely ground 250 250 250 250 limestone (g) wt % plasticizer 0 0.1 0.1 0.1 based on -HH w/g 0.87 0.87 0.87 0.87 slump (cm) 13.9 17.2 17.3 18.9 Inventive example 2, comprising the inventive pulverulent composition, displays a marked increase in the slump, of 36% relative to the blank value and of 10% and 9% relative to the plasticizer solution and to the plasticizer in powder form, respectively.
Dispersing of the Product with Water
Production of Inventive Pulverulent Composition in a Mill

(23) 250 g of -HH are charged to a Grindomix knife mill from Retsch GmbH. A 50 wt % strength aqueous solution of copolymer 1 is applied to the binder by pipette in a quantity sufficient to give an active ingredient content of 0.1 wt % based on -HH. The material with plasticizer is subsequently mixed at 8000 rpm for 10 seconds. After a short break in mixing, of a few seconds, the mixture is mixed again for a further 10 seconds.

Inventive Example 3

(24) Use of the inventive pulverulent composition as binder in a blend with finely ground limestone (Omyacarb 130 AL) in a ratio of 1:1.

Comparative Example 7

(25) Blend of untreated -HH with finely ground limestone (Omyacarb 130 AL) in a ratio of 1:1, where the 50 wt % strength aqueous solution of copolymer 1 is added to the mixing water.

Comparative Example 8

(26) Blend of untreated -HH with finely ground limestone (Omyacarb 130 AL) in a ratio of 1:1, where copolymer 1 is added as a powder to the dry component.

Application Example 3

(27) 500 g of a mixture consisting of 250 g of -HH and 250 g of finely ground limestone (Omyacarb 130 AL) are homogenized in dry form and charged to the mixing vessel of a forced mixer. In the case of inventive example 1, the binder has already been treated with 0.1 wt % of copolymer 1. In the case of inventive examples 2 and 3, the plasticizer is added in liquid form to the mixing water or as powder to the dry component, respectively. In both cases the active ingredient concentration is likewise 0.1 wt % of copolymer 1, based on the -HH. The pulverulent mixture of -HH, finely ground limestone, and copolymer 1 is stirred at 950 rpm for 60 sec, with the amount of water required, corresponding to a w/g of 0.8, being added after 5-10 seconds.

(28) During the mixing operation, a note is taken of the time required to give a homogeneous mixture. The results of the application tests for inventive example 3 and for comparative examples 7 and 8 are set out in table 3.

(29) TABLE-US-00004 TABLE 3 Determination of the time to homogeneous dispersing of the product with water (blend of -HH and finely ground limestone, 1:1) Wt % of copolymer Time 1 based on -HH (seconds)* Inventive example 3 0.1 9 (according to the invention) Comparative example 7 0.1 13 Comparative example 8 0.1 16 *Time required for homogeneous dispersing of the product to be achieved.

(30) The inventive pulverulent composition according to inventive example 3 requires a time which is lower by 31% and 44% than in comparative examples 7 and 8, respectively, until homogeneous dispersing of the product has been achieved.