Gypsum-containing composition

Abstract

The invention relates to a composition comprising at least one binder based on calcium sulfate and at least one polymer obtainable by polymerization of monomers based on alkoxylates of S-vinylthioalkanols. Furthermore a molding, in particular a gypsum plasterboard, a gypsum wallboard, a screed or a knifing filler, obtained by setting of the composition of the invention is disclosed.

Claims

1. A composition comprising A) at least one binder based on calcium sulfate and B) at least one polymer obtainable by polymerization of monomers comprising an unsaturated compound of the general formula (I) ##STR00010## where R.sup.1, R.sup.2, R.sup.3 are identical or different and are each, independently of one another, H, or CH.sub.3, R.sup.4 is linear or branched C.sub.1-C.sub.30-alkylene, R.sup.5, R.sup.6 are identical or different and are each, independently of one another, H, C.sub.1-C.sub.20-alkyl, C.sub.3-C.sub.15-cycloalkyl, aryl, CH.sub.2OC.sub.1-C.sub.20-alkyl, or CH.sub.2OC.sub.2-C.sub.20-alkenyl, where R.sup.5 and R.sup.6 can together also form a C.sub.3-C.sub.6-alkylene, R.sup.7 is H, C.sub.1-C.sub.4-alkyl, or ##STR00011## R.sup.8 is C.sub.1-C.sub.22-alkyl, or C.sub.2-C.sub.22-alkenyl, and n is an integer from 2 to 200.

2. The composition according to claim 1, wherein R.sup.4 is a C.sub.2-C.sub.4-alkylene group, R.sup.5, R.sup.6 are identical or different and are each, independently of one another, a group selected from among H, CH.sub.3, CH.sub.2CH.sub.3, C.sub.3-C.sub.11-alkyl, C.sub.12-C.sub.22-alkyl, phenyl, CH.sub.2OC.sub.1-C.sub.10-alkyl, and CH.sub.2OC.sub.2-C.sub.10-alkenyl, R.sup.7 is H or C.sub.1-C.sub.4-alkyl and n is from 5 to 140.

3. The composition according to claim 1, wherein the unsaturated compounds are unsaturated compounds (Ia) ##STR00012## where R.sup.3 is H or methyl, R.sup.4 is a linear or branched C.sub.2-C.sub.10-alkylene group, R.sup.5, R.sup.6 are each, independently of one another, H, methyl or ethyl, with the proviso that the sum of the carbon atoms in the radicals R.sup.5 and R.sup.6 is in each case from 0 to 2 per alkoxy group, and n is from 5 to 160.

4. The composition according to claim 1, wherein the unsaturated compounds are unsaturated compounds (Ib) ##STR00013## where n is from 20 to 140.

5. The composition according to claim 4, wherein n is from 60 to 140.

6. The composition according to claim 1, wherein the polymer comprises at least one further monomer which is different from the unsaturated compound of the general formula (I) in the polymer.

7. The composition according to claim 6, wherein the at least one further monomer is at least one monoethylenically unsaturated monomer comprising at least one acid group, where the acid group can optionally be entirely or partly neutralized.

8. The composition according to claim 7, wherein the acid group is at least one group selected from the group consisting of carboxylic acid, sulfonic acid, phosphoric acid and phosphonic acid groups.

9. The composition according to claim 8, wherein the polymer comprises at least one monomer having phosphoric or phosphonic acid groups selected from the group consisting of vinylphosphonic acid, esters of hydroxyethyl, hydroxypropyl or hydroxybutyl (meth)acrylate with (poly)phosphoric acid, monovinyl phosphate, allylphosphonic acid, monoallyl phosphate, 3-butenylphosphonic acid, mono-3-butenyl phosphate, mono(4-vinyloxybutyl) phosphate, mono(2-hydroxy-3-vinyloxypropyl) phosphate, mono(1-phosphonoxymethyl-2-vinyloxyethyl) phosphate, mono(3-allyloxy-2-hydroxypropyl) phosphate, mono-2-(allylox-1-phosphonoxymethylethyl) phosphate, 2-hydroxy-4-vinyloxymethyl-1,3,2-dioxaphosphole, 2-hydroxy-4-allyloxymethyl-1,3,2-dioxaphosphole and salts thereof.

10. The composition according to claim 1, wherein from 5 to 99.9% by weight of unsaturated compounds of the general formula (I), based on the total amount of monomers, are comprised in the polymer.

11. The composition according to claim 7, wherein from 5 to 99.9% by weight of unsaturated compounds of the general formula (I) and from 95 to 0.1% by weight of further monoethylenically unsaturated monomers, in each case based on the total amount of monomers, are comprised in the polymer.

12. The composition according to any claim 7, wherein the binder based on calcium sulfate is -hemihydrate, /-hemihydrate, -hemihydrate, natural anhydrite, synthetic anhydrite, anhydrite obtained from flue gas desulfurization and/or mixtures of two or more thereof.

13. The composition according to claim 7, wherein the composition comprises, based on the dry mass, at least 10% by weight of A) the at least one binder based on calcium sulfate and from 0.005 to 5% by weight of B) the at least one polymer.

14. The composition according to claim 1, wherein from 5 to 99.9% by weight of unsaturated compounds of the general formula (I) and from 95 to 0.1% by weight of further monoethylenically unsaturated monomers, in each case based on the total amount of monomers, are comprised in the polymer.

15. The composition according to claim 1, wherein the binder based on calcium sulfate is -hemihydrate, /-hemihydrate, -hemihydrate, natural anhydrite, synthetic anhydrite, anhydrite obtained from flue gas desulfurization and/or mixtures of two or more thereof.

16. The composition according to claim 1, wherein the composition comprises, based on the dry mass, at least 10% by weight of A) the at least one binder based on calcium sulfate and from 0.005 to 5% by weight of B) the at least one polymer.

17. A molding produced by setting of a composition according claim 7.

18. The molding according to claim 17, wherein the molding is a gypsum plasterboard, gypsum wallboard, screed or a knifing filler.

19. A molding produced by setting of a composition according to claim 1.

20. The molding according to claim 19, wherein the molding is a gypsum plasterboard, gypsum wallboard, screed or a knifing filler.

Description

EXAMPLES

Overview

(1) TABLE-US-00001 TABLE 1 Side chain type Loading Side chain:loading Example 1 VME-135 EO HEMA-P 1:4.5 Example 2 VME-135 EO Acrylic acid 1:4.5 Comparative VOB-135 EO HEMA-P 1:4.5 example 1 Comparative VOB-135 EO HEA-P 1:5.0 example 2 VME-135 EO: H.sub.2CCHSCH.sub.2CH.sub.2(OCH.sub.2CH.sub.2).sub.135OH VOB-135 EO: H.sub.2CCHOCH.sub.2CH.sub.2CH.sub.2CH.sub.2(OCH.sub.2CH.sub.2).sub.135OH HEMA-P: Hydroxyethyl methacrylate phosphate HEA-P: 2-Hydroxyethyl acrylate phosphate
Gel Permeation Chromatography (GPC)

(2) The sample preparation for the molecular weight determination was carried out by dissolving copolymer solution in the GPC eluent, so that the polymer concentration in the GPC eluent is 0.5% by weight. This solution was then filtered through a syringe attachment filter having a polyether sulfone membrane and pore size of 0.45 m. The injection volume of this filtrate was 50-100 l.

(3) The determination of the average molecular weights was carried out on a GPC instrument from Waters having the model name Alliance 2690 with UV detector (Waters 2487) and RI detector (Waters 2410). Columns: Shodex SB-G Guard Column for SB-800 HQ series Shodex OHpak SB 804HQ and 802.5HQ (PHM gel, 8300 mm, pH 4.0 to 7.5) Eluent: 0.05 M aqueous ammonium formate/methanol mixture=80:20 (by volume) Flow rate: 0.5 ml/min Temperature: 50 C. Injection: 50 to 100 l Detection: RI and UV

(4) The molecular weights of the copolymers were determined relatively to polyethylene glycol standards from PSS Polymer Standards Service GmbH. The molecular weight distribution curves of the polyethylene glycol standards were determined by means of light scattering. The masses of the polyethylene glycol standards were 682 000, 164 000, 114 000, 57 100, 40 000, 26 100, 22 100, 12 300, 6240, 3120, 2010, 970, 430, 194, 106 g/mol.

(5) Synthesis of the Dispersants According to the Invention

(6) Synthesis of the Monomer According to the Invention (VME-135 EO):

(7) Reaction Scheme for the Preparation of VME-135 EO:

(8) ##STR00009##

(9) 23.4 g (224 mmol) of vinylmercaptoethanol and 120 mg (1.71 mmol) of potassium methoxide together with 50 ml of toluene were placed at 60 C. in a 2 liter autoclave and flooded with nitrogen. The temperature was subsequently increased to 120 C. 1332 g (30.2 mol) of ethylene oxide were introduced over a period of 36 hours. The reaction mixture obtained was stirred further at 120 C. for 12 hours and, after cooling to 100 C., freed of volatile constituents under reduced pressure.

(10) This gave 1388 g of a light-brown solid.

(11) OHN=12.1 mg KOH/g (theory: 9.3 mg KOH/g), PEG content: 2.0% by weight

Example 1

(12) Copolymer of 84% by Weight of VME-135 EO and 16% by Weight of HEMA-P

(13) The experimental apparatus consists of 1000 ml double-wall reactor, thermostat, stirring motor with propeller stirrer, temperature sensor, pH probe and N.sub.2 feed conduit. 172.80 g of water and 106.38 g of VME-135 EO are placed in the reactor. N.sub.2 is subsequently introduced and the oxygen is displaced. The thermostat is set to T=75 C. and the contents of the reactor are heated.

(14) At about 60 C., 19.79 g of HEMA-P in 104.6 g of water are added. A pH of about 1.0-1.5 is established. 7.05 g of 50% strength NaOH are then added in order to set a pH of about 3. During the addition of the HEMA-P solution, the temperature drops to 50 C. The contents of the reactor are subsequently heated to 60 C. 1.26 g of Wako VA-044 (2,2-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride) in 11.3 g of water are then added. After a reaction time of 3 hours, the contents of the reactor are cooled to 25 C.

(15) The yellowish slightly turbid product formed has a pH of about 2.5 and a solids content of 33% by weight. The average molar mass of the polymer (Mw) is 29 000 g/mol. the polydispersity is 1.35.

(16) The results are summarized in table 2.

(17) TABLE-US-00002 TABLE 2 Overview of the analytical data Example Mw g/mol Solids PD 1 29 000 33 1.35

Example 2

(18) Copolymer of 94.9% by Weight of VME-135 EO and 5.1% by Weight of Acrylic Acid

(19) The experimental apparatus consists of 1000 ml double-wall reactor, thermostat, stirring motor with propeller stirrer, temperature sensor, pH probe and N.sub.2 feed conduit. 172.80 g of water and 106.38 g of VME-135 EO are placed in the reactor. N.sub.2 is subsequently introduced and the oxygen is displaced. The thermostat is set to T=40 C. and the contents of the reactor are heated.

(20) A solution 1 consisting of 5.78 g of acrylic acid (99.5% strength) and 30.36 g of water and a solution 2 consisting of 1.12 g of Wako VA-044 (2,2-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride) in 10.09 g of water are produced.

(21) At about 30 C., 1.8 ml of solution 1 and 0.06 g of 3-mercaptopropionic acid (99% strength) are added. A pH of about 4.0 is established.

(22) 0.57 g of 3-mercaptopropionic acid is added to the remaining solution 1.

(23) 0.6 ml of solution 2 is introduced into the reactor.

(24) The thermostat is set to T=78 C., and the contents of the reactor are subsequently heated to about 60 C.

(25) At about 60 C. and a pH of about 4.0, the introduction of the remaining solution 1 over a period of 180 minutes at a rate of 11.5 ml/h and the remaining solution 2 over a period of 240 minutes at a rate of 2.7 ml/h are commenced.

(26) 10 minutes after commencement of the addition (internal T about 65 C.), the thermostat is set to 70 C.

(27) The mixture is subsequently stirred for another 120 minutes for after-reaction to occur and the contents of the reactor are then cooled to 25 C. The pH of about 3.0 is adjusted to about 8.4 using 6.66 g of NaOH (50% strength).

(28) The yellowish slightly turbid product formed has a pH of about 8.4 and a solids content of 37% by weight. The average molar mass of the polymer (Mw) is 50 000 g/mol. The polydispersity is 1.33.

(29) The results are summarized in table 3.

(30) TABLE-US-00003 TABLE 3 Overview of the analytical data Example Mw g/mol Solids PD 2 50 000 37 1.33

Comparative Example 1

(31) The experimental apparatus consists of 1000 ml double-wall reactor, thermostat, stirring motor with propeller stirrer, temperature probe, pH probe and N.sub.2 feed conduit.

(32) 170.0 g of water and 202.12 g of VOB-135 EO are placed in the reactor. N.sub.2 is subsequently introduced and the oxygen is displaced. The thermostat is set to T=40 C. and the contents of the reactor are heated.

(33) At about 35 C., 37.59 g of HEMA-P (99.99% strength) in 87.72 g of water are added. A pH of about 1.5 is established. 10.20 g of (50% strength) NaOH are then added in order to set a pH of about 3. The thermostat is set to T=75 C. and the contents of the reactor are heated further. At about 65 C., 2.40 g of Wako VA-044 (2,2-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride) in 21.6 g of water are added.

(34) After 15 minutes, the thermostat is set to T=70 C.

(35) After a reaction time of 3 hours, the contents of the reactor are cooled to 20 C. The contents of the reactor are brought to a pH of about 8.1 using 20.16 g of NaOH (50% strength).

(36) The brownish slightly turbid product formed has a solids content of 47% by weight. The average molar mass of the polymer (Mw) is 35 200 g/mol. The polydispersity is 1.57.

(37) TABLE-US-00004 TABLE 4 Overview of the analytical data Comparative example Mw g/mol Solids PD 1 35 200 46.8 1.57

Comparative Example 2

(38) 108.7 g of deionized water and 112.5 g of VOB-135 EO are placed in a glass reactor equipped with stirrer, pH electrode, thermometer, redox electrode, N.sub.2 inlet and cooled to a polymerization commencement temperature of 15 C. (initial charge).

(39) In a separate feed vessel, 22.12 g of HEA-P are homogeneously mixed with 199.08 g of deionized water and 9.7 g of (50% strength) NaOH (solution A). In parallel, a 6% solution of a mixture of sodium sulfite, the disodium salt of 2-hydroxy-2-sulfinatoacetic acid and the disodium salt of 2-hydroxy-2-sulfonatoacetic acid (Brggolit FF6 from Brggemann GmbH) in water is produced (solution B). While stirring and cooling, 109.53 g of solution A are firstly added to the initial charge and 0.77 g of 3-mercaptopropionic acid (MPA) is then added to the remaining solution A. Subsequently, 0.14 g of 3-mercaptopropionic acid and 0.089 g of iron(II) sulfate heptahydrate (FeSO.sub.4) are added in succession to the initial charge solution. This is subsequently set to a starting pH of 5.3 using NaOH (50% strength).

(40) The reaction is started by the addition of 0.75 g of hydrogen peroxide (30% strength solution in water) to the initial charge mixture. At the same time, the introduction of solution A and solution B to the stirred initial charge is commenced. Solution A is introduced over a period of 30 minutes. Solution B is introduced in parallel at a constant metering rate of 13.5 ml/h until no more peroxide can be detected in the solution. The polymer solution obtained is subsequently brought to a pH of 6.5 using 50% strength sodium hydroxide solution.

(41) The copolymer obtained is obtained in a solution which has a solids content of 29.3% by weight. The weight average molar mass of the copolymer is 40 400 g/mol, and the polydispersity is 1.6.

(42) TABLE-US-00005 TABLE 5 Overview of the analytical data Comparative example Mw g/mol Solids PD 2 40 400 29.3 1.6

Use Examples

(43) The dispersants from the synthesis examples are examined to determine their properties as gypsum plasticizers in a suitable test system.

(44) 300 g of -hemihydrate from flue gas desulfurization are firstly prehomogenized with finely milled calcium sulfate dihydrate (gypsum) as accelerator and sprinkled into 187 g of water. The dispersant is mixed into the make-up water beforehand. The mixture is subsequently allowed to stand for 15 seconds. Stirring with a Hobart mixer for a further 15 seconds at the setting II (285 revolutions per minute) is then commenced. After filling of a cylinder (h=10 cm, d=5 cm), which is lifted after 60 seconds, the spread is determined. The solidification time is determined by the knife cut method (in accordance with DIN EN 13279-2).

(45) TABLE-US-00006 TABLE 6 Use examples at a water to gypsum ratio of 0.655. Accelerator Spread Knife cut Dispersant FM % [g] [cm] [min:sec] Water Comparative 0.12 0.028 15.8 2:20 0.655 example 1 Comparative 0.12 0.150 20.5 2:15 0.655 example 2 Example 1 0.07 0.035 20.2 2:20 0.655 Example 2 0.10 0.057 20.1 2:30 0.655 FM % = Amount of dispersant (solids) used based on the amount of -hemihydrate in percent by weight. Accelerator = Amount of finely milled calcium sulfate dihydrate (gypsum) used.

(46) Example 1 according to the invention displays a very good plasticizing effect, which can be seen from the small dosage of dispersant in order to achieve the same spread compared to a polyphosphate ether based on VOB-135 EO and HEA-P (comparative example 2).

(47) Even at virtually twice the dosage compared to example 1, the same plasticizing effect cannot be achieved when using a polyphosphate ether based on VOB-135 EO and HEMA-P (comparative example 1).

(48) Example 2 according to the invention based on acrylic acid also displays a very good plasticizing effect.