BRANCHED COPOLYMERS AS DISPERSANTS FOR MINERAL BINDERS

Abstract

The invention relates to the use of branched copolymers as dispersants of mineral binders, wherein the copolymers are formed from (1) at least one olefinically unsaturated carboxylic acid monomer (2) at least one olefinically unsaturated macromonomer of the general structure (I)

##STR00001## where R.sup.1 is an olefinically unsaturated radical which has 2-10 carbon atoms and may optionally be substituted by oxygen and/or nitrogen, preferably vinyl, allyl, methallyl, vinyloxybutyl, isoprenyl, acryloyl and/or methacryloyl, X=O or NH, A is in each case independently C1-C10 alkylene, preferably ethylene, propylene and/or butylene, R.sup.2=C1-C16 alkyl, B is in each case independently C1-C10 alkylene, preferably ethylene, propylene and/or butylene, m is in each case independently an integer in the range of 0-350, preferably 2-200, more preferably 5-150, especially 7-30, n is an integer in the range of 0-100, preferably 1-100, more preferably 2-75, most preferably 5-55, p is 0 or 1, preferably 0, o is an integer in the range of 1-50, preferably 3-40, more preferably 6-30, especially 8-20, and q is an integer in the range of 1-10.

Claims

1. A copolymer, the copolymer having repeating units formed from (1) at least one olefinically unsaturated carboxylic acid monomer, and (2) at least one olefinically unsaturated macromonomer of the general structure (I) ##STR00016## where R.sup.1 is an olefinically unsaturated radical which has 2-10 carbon atoms and may optionally be substituted by oxygen and/or nitrogen, X is O or NH, A is in each case independently a C1-C10 alkylene, R.sup.2 is a C1-C16 alkyl, B is in each case independently a C1-C10 alkylene, m is in each case independently an integer in the range of 0-350, n is an integer in the range of 0-100, p is 0 or 1, o is an integer in the range of 1-50, and q is an integer in the range of 1-10.

2. The copolymer as claimed in claim 1, wherein the at least one unsaturated carboxylic acid monomer is a monomer of the general structures (IIa) or (IIb) ##STR00017## where R.sup.3 is a H or a C1-C6-alkyl chain, R.sup.4 is a H, C(O)Y, or a C1-C6-alkyl chain, and Y is OM, with M selected from H, alkali metals, alkaline earth metals or organic ammonium, or Y is NR.sup.4R.sup.5 with R.sup.4 and R.sup.5 independently being H or a C1-C6-alkyl chain; ##STR00018## where Z is O or NR.sup.5 and R.sup.3 has the definitions as above, and R.sup.5 is a H or a C1-C6-alkyl chain.

3. The copolymer as claimed in claim 1, wherein in the general structure (I), X is O, p is 0, m is in each case independently an integer in the range of 5-150, n is an integer in the range of 5-55, and o is an integer in the range of 8-50.

4. The copolymer as claimed in claim 1, wherein the proportion of ethylene oxide units in the polyalkylene oxide chains (AO).sub.m and (BO).sub.m, based on all alkylene oxide units AO and BO present, is more than 90 mol %.

5. The copolymer as claimed in claim 1, wherein the molar ratio of the at least one olefinically unsaturated carboxylic acid monomer to the at least one olefinically unsaturated macromonomer of the general structure (I) is in the range of 0.3-30.

6. The copolymer as claimed in claim 1, wherein the copolymer further comprises at least one additional repeating unit formed from a monomer M selected from the group consisting of styrene, ethylene, propylene, butylene, butadiene, isoprene, vinyl acetate, vinyl chloride, acrylonitrile, N-vinylpyrrolidone, hydroxyalkyl (meth)acrylates and a monomer of the general structure (VI) ##STR00019## where R.sup.6 is in each case independently H, CH.sub.2COOM or an alkyl group having 1 to 5 carbon atoms, R.sup.7 is in each case independently H or an alkyl group having 1 to 5 carbon atoms, R.sup.8 is in each case independently H, COOM or an alkyl group having 1 to 5 carbon atoms, r is 0, 1 or 2, s is 0 or 1, t is 0, or an integer from 1 to 4, u=2-250, X, in each case independently, is O or NH, R.sup.9 is in each case independently H, a C.sub.1 to C.sub.20 alkyl group, cyclohexyl group or alkylaryl group, and D is a C.sub.2 to C.sub.4 alkylene.

7. A composition comprising: at least one mineral binder and at least one copolymer as claimed in claim 1, wherein the at least one copolymer is present in the composition in an amount effective to act as a dispersant for the at least one mineral binder, and an average molar mass Mw of the at least one copolymer is in the range of 1,000-1,000,000 g/mol.

8. The composition as claimed in claim 7, wherein the at least one mineral binder is selected from the group consisting of cement, portland cement, aluminate cement, -calcium sulfate hemihydrate, -calcium sulfate hemihydrate, anhydrite, lime, industrial slags, synthetic slags, blast furnace slags, foundry sand, foundry sand flour, electrothermal phosphorus slags, copper slags, stainless steel slags, pozzolans, fly ashes, microsilica, metakaolin, natural pozzolans, tuff, trass, volcanic ash, natural zeolites, synthetic zeolites, and burnt oil shale.

9. The composition as claimed in claim 7, wherein the at least one copolymer is present in an amount of 0.01-10% by weight based on the content of the at least one mineral binder.

10. A multistage process for preparing the copolymer as claimed in claim 1, comprising the steps of 1) forming a first reaction product by reacting an alcohol or amine R.sup.1XH with alkylene oxide and/or a halogenated alcohol or amine Hal-R.sup.2XH, where R.sup.1 is an olefinically unsaturated radical which has 2-10 carbon atoms and may optionally be substituted by oxygen and/or nitrogen, X is O or NH, Hal is a halide and R.sup.2 is a C.sub.1-C.sub.16 alkyl, 2) forming a second reaction product by reacting the first reaction product from step 1) with glycidol or epichlorohydrin or a mixture of glycidol and alkylene oxide or epichlorohydrin and alkylene oxide, 3) forming a third reaction product by reacting the second reaction product from step 2) with alkylene oxide, and 4) forming a fourth reaction product by free-radically polymerizing a mixture of at least one olefinically unsaturated carboxylic acid monomer with the third reaction product from step 3).

11. The multistage process as claimed in claim 10, further comprising 5) drying the fourth reaction product from step 4).

12. A mineral binder or mineral binder composition comprising at least one mineral binder, and at least one copolymer obtained from the multistage process as claimed in claim 10.

13. The mineral binder or mineral binder composition as claimed in claim 12, comprising 0.01-10% by weight, based on the content of the at least one mineral binder, of the at least one copolymer obtained from a multistage process comprising the steps of 1) forming a first reaction product by reacting an alcohol or amine R.sup.1XH with alkylene oxide and/or a halogenated alcohol or amine Hal-R.sup.2XH, where R.sup.1 is an olefinically unsaturated radical which has 2-10 carbon atoms and may optionally be substituted by oxygen and/or nitrogen, X is O or NH, Hal is a halide and R.sup.2 is a C.sub.1-C.sub.16 alkyl, 2) forming a second reaction product by reacting the first reaction product from step 1) with glycidol or epichlorohydrin or a mixture of glycidol and alkylene oxide or epichlorohydrin and alkylene oxide, 3) forming a third reaction product by reacting the second reaction product from step 2) with alkylene oxide, and 4) free-radically polymerizing a mixture of at least one olefinically unsaturated carboxylic acid monomer with the third reaction product from step 3).

14. An additive for mineral binder compositions, comprising at least one copolymer obtained from the multistage process as claimed in claim 10.

15. The additive as claimed in claim 14, further comprising one or more polycarboxylate ethers.

16. A shaped body obtained by curing the mineral binder or the mineral binder composition as claimed in claim 12.

17. The copolymer as claimed in claim 1, wherein m is in each case independently an integer in the range of 2-200.

Description

EXAMPLES

Synthesis Example 1

Preparation of the Macromonomer M-1

[0196] Step 1: In a reactor inertized with N.sub.2 gas, 4 g (0.074 mol) of sodium methoxide is dissolved in 464 g (8 mol) of allyl alcohol and heated to 100 C. This is followed by metered addition of 1760 g (40 mol) of ethylene oxide over the course of 5 hours. In the course of this, the temperature is kept at 100 to 140 C. and the pressure at 1 to 3 bar. After the metered addition has ended, the reaction mixture is stirred at 140 C. for 2 hours. Subsequently, the mixture is cooled to 30 C. [0197] Step 2: In a reactor inertized with N.sub.2 gas, 0.54 g (0.01 mol) of sodium methoxide is added to 117 g (0.42 mol) of the mixture from step 1) and heated to 130 C. This is followed by metered addition of 93 g (1.26 mol) of glycidol over the course of 30 minutes. In the course of this, the temperature is kept at 130 to 140 C. and the pressure at 1 to 3 bar. After the metered addition has ended, the reaction mixture is stirred at 140 C. for 2 hours. The mixture is left to cool to 50 C. [0198] Step 3: After cooling to 50 C., 2.2 g (0.04 mol) of sodium methoxide is added to the mixture from step 2). The reactor is inertized again with N.sub.2 gas and heated to 130 C. This is followed by metered addition of 628 g (14.27 mol) of ethylene oxide over the course of 4 hours. In the course of this, the temperature is kept at 130 to 140 C. and the pressure at 0 to 3 bar. After the metered addition has ended, the reaction mixture is stirred at 140 C. for 3 hours. Subsequently, the mixture is cooled to 50 C. and neutralized with 3.2 g (0.054 mol) of acetic acid. The resultant mixture is the macromonomer M-1.

Synthesis Example 2

Preparation of the Copolymer C-1

[0199] A reactor inertized with N.sub.2 gas is initially charged with 70 g of water, 57 g (0.05 mol) of macromonomer M-1, 27 g (0.05 mol) of an allyl alcohol-started polyethylene glycol (11 EO units), 26 g (0.36 mol) of acrylic acid, 50 g of a 16% aqueous NaOH solution, 0.8 g of a 10% aqueous solution of Fe(II)SO.sub.4.Math.7H.sub.2O and 1.1 g of sodium hypophosphite. While stirring, 5.5 g of a 30% aqueous hydrogen peroxide solution and 2.3 g of a 5% aqueous Rongalit solution are added dropwise and simultaneously at a temperature of 20-35 C. over the course of 70 min. 120 min after commencement of the addition, a clear solution of copolymer C-1 is obtained.

[0200] The following table gives an overview of the copolymers used:

TABLE-US-00001 TABLE 1 Copolymers used R-1 Aqueous solution of a PCE (55% dry matter) formed from acrylic acid (3.6 mol) and ethoxylated methallyl alcohol (Mw = 2400 g/mol; 1 mol) C-1 Copolymer from synthesis example 2

Use Example 1

Mortar Test

[0201] A dry mix was produced, consisting of 150 g of cement (CEM I 42.5 N from Vigier Holding AG), 5.8 g of microsilica (SikaFume-HR/-TU, available from Sika Schweiz AG), 69.2 g of blast furnace slag (Regen GGBS from Hanson UK) and 41.5 g of limestone (Nekafill 15 from Kalkfabrik Netstal AG). For production of the dry mix, the constituents were dry mixed in a Hobart mixer for 30 seconds. Added to this dry mixture were the additives specified in table 2, each dissolved in 60 g of water. Mixing was continued at level 1 for 30 seconds, and finally at level 2 for 3.5 minutes.

[0202] The spread of the mortar obtained was measured to DIN EN 12350-5. In addition, the funnel flow time was measured to DIN EN 12350-9.

[0203] The air content was ascertained 30 minutes after makeup according to standard DIN EN 12350-7.

[0204] The following table gives an overview of the results:

TABLE-US-00002 TABLE 2 Results of the mortar tests Spread Funnel flow Air content Test Additive* [mm] time [s] [%] V-1 3% R-1 165 215 1.6 E-1 3% C-1 162 150 1.2 E-2 3% C-1 162 142 4.4 1% LP *dosage in percent by weight relative to the dry weight of the cement LP: Air pore former consisting of 1% by weight of alum inum powder (particle size D50 = 5 m, screen residue at 45 m of <0.1% by weight), 0.5% by weight of distilled tall oil, 98.5% by weight of calcium carbonate powder.