Polycondensate based water-reducer

Abstract

The present invention relates to polycondensates containing at least a structural unit, which is an aromatic moiety bearing a polyether side chain, at least a structural unit, which is an aromatic moiety bearing at least one phosphoric acid monoester group, at least a structural unit, which is an aromatic moiety, bearing at least one hydroxy group and at least a methylene unit (—CH.sub.2—), which is attached to two aromatic structural units. The invention also concerns a process for the production of the polycondensates, their use for the dispersion of inorganic binders, for increasing the strength development of concrete and for improving the slump-retention of concrete. The invention relates also to building material mixtures comprising the polycondensates and inorganic binders.

Claims

1. A polycondensate containing (I) at least a structural unit, which is an aromatic moiety bearing a polyether side chain comprising alkylene glycol units, with the proviso that the number of ethylene glycol units in the side chain is from 9 to 130 and that the content of ethylene glycol units is higher than 80 mol % with respect to all alkylene glycol units in the polyether side chain, (IIa) at least a structural unit, which is an aromatic moiety bearing at least one phosphoric acid monoester group and/or its salt, with the proviso that the molar ratio of (IIa):(I) is from 0.25 to 8, (IIb) at least a structural unit with a molar mass lower than 200 g/mol, which is an aromatic moiety with 6 carbon atoms bearing at least one hydroxy group attached to the aromatic moiety with the proviso that the molar ratio of (IIa):(IIb) is from 0.2 to 1.5, (III) at least a methylene unit (—CH.sub.2—), which is attached to two aromatic structural units Y, where aromatic structural units Y, independently of one another, are identical or different and are represented by structural unit (I), structural unit (IIa), structural unit (IIb) or optionally (IV) aromatic structural units of the polycondensate, which are different from structural unit (I), structural unit (IIa) and structural unit (IIb).

2. The polycondensate according to claim 1, in which a monomer (M-IIb) is used for the introduction of the structural unit (IIb) in a polycondensation reaction leading to the polycondensate and the solubility of the monomer (M-IIb) in water is higher than 10 g/l at pH=4, 20° C. and atmospheric pressure.

3. The polycondensate according to claim 1, in which the solubility in water of the polycondensate is higher than 300 g/l, the solubility of the polycondensate being measured at 20° C., atmospheric pressure and a pH of 4.

4. The polycondensate according to claim 1, in which the structural units (I), (IIa) and (IIb) are represented by the following general formulae ##STR00009## where A are identical or different and are represented by a substituted or unsubstituted aromatic or heteroaromatic compound having 5 to 10 atoms in the aromatic ring, where B are identical or different and are represented by N, NH or O, where n=2 if B=N and n=1 if B=NH or O, where R.sup.1 and R.sup.2, independently of one another, are identical or different and are represented by a branched or straight-chain C.sub.1- to C.sub.10-alkyl radical, C.sub.5- to C.sub.8-cycloalkyl radical, aryl radical, heteroaryl radical or H, with the proviso that the content of ethylene glycol units is higher than 80 mol % with respect to all alkylene glycol units in the polyether side chain, where a are identical or different and are represented by an integer from 9 to 130, where X are identical or different and are represented by a branched or straight-chain C.sub.1- to C.sub.10-alkyl radical, C.sub.5- to C.sub.8-cycloalkyl radical, aryl radical, heteroaryl radical or H, ##STR00010## where D are identical or different and are represented by a substituted or unsubstituted heteroaromatic compound having 5 to 10 atoms in the aromatic ring, where E are identical or different and are represented by N, NH or O, where m=2 if E=N and m=1 if E=NH or O, where R.sup.3 and R.sup.4 independently of one another, are identical or different and are represented by a branched or straight-chain C.sub.1- to C.sub.10-alkyl radical, C.sub.5- to C.sub.8-cycloalkyl radical, aryl radical, heteroaryl radical or H, where b are identical or different and are represented by an integer from 1 to 20, where M independently of one another is identical or different and is H or a cation equivalent, (GF-IIb)
F—OH where F is represented by an aromatic moiety with 6 carbon atoms in the aromatic ring.

5. The polycondensate according to claim 1, in which the structural unit (IIa) is an alkoxylated, hydroquinone phosphoric acid monoester according to the following general formula (GF-V)
-[[M.sub.2O.sub.3P-(AO).sub.p]—O—C.sub.6H.sub.2—O-[(AO).sub.p—PO.sub.3M.sub.2]]-,  (GF-V) p is an integer from 1 to 20, A is an alkylene with 2 to 5 carbon atoms, M independently of one another is identical or different and is H or a cation equivalent.

6. The polycondensate according to claim 1, in which the weight average molecular weight (Mw) of the polycondensate is from 8,000 g/mol to 70,000 g/mol.

7. The polycondensate according to claim 1, in which the structural unit (I) is derived from an alkoxylated aromatic alcohol monomer bearing a hydroxyl group at the end of the polyether side chain.

8. The polycondensate according to claim 1, in which the structural unit (I) is a phenyl poly alkylene glycol.

9. The polycondensate according to claim 1, in which the structural unit (IIa) is derived from an aromatic alcohol monomer, which was in a first step alkoxylated, and the obtained alkoxylated aromatic alcohol monomer bearing a hydroxyl group at the end of the polyether side chain was in a second step phosphorylated to yield the phosphoric acid monoester group.

10. The polycondensate according to claim 1, in which the molar ratio of the sum of structural unit(s) (I), (IIa) and (IIb) to the structural units (IV) is higher than 1/1.

11. The polycondensate according to claim 1, where in (I) the number of ethylene glycol units in the side chain is from 9 to 50 and the content of ethylene glycol units is higher than 80 mol % with respect to all alkylene glycol units in the polyether side chain, and wherein the polycondensation degree of the polycondensate containing the units (I), (IIa), (IIb) and optionally (IV) is in the range from 10 to 75.

12. A process (A) for the production of the polycondensate according to claim 1, wherein the following monomers are reacted in the presence of an acid catalyst: (I) a monomer comprising an aromatic moiety bearing a polyether side chain comprising alkylene glycol units, with the proviso that the number of ethylene glycol units in the side chain is from 9 to 130 and that the content of ethylene glycol units is higher than 80 mol % with respect to all alkylene glycol units in the polyether side chain, (IIa) a monomer comprising an aromatic moiety bearing at least one phosphoric acid monoester group and/or its salt, (IIb) a monomer comprising an aromatic moiety with 6 carbon atoms, bearing at least one hydroxy group attached to the aromatic moiety and (III) the monomer formaldehyde.

13. The process according to claim 12, characterized in that the acid catalyst is present in the form of the monomer (IIb), which is an aromatic moiety with 6 carbon atoms, comprising at least one hydroxy group and at least one sulphonic acid group, in each case attached to the aromatic ring.

14. A building material mixture comprising one or more polycondensates according to claim 1 and one or more inorganic binders selected from the group of α-calcium sulfate hemihydrate, β-calcium sulfate hemihydrate, calcium sulfate in the form of anhydrite, slag sand, fly ash, fumed silica, blast furnace slag, natural pozzolanes, burnt oil shale, and cement, optionally wherein Portland cement is present in a proportion greater than 40% by weight based on the total amount of the inorganic binder.

15. A method comprising dispersing with the polycondensates according to claim 1, inorganic binders, selected from the group of α-calcium sulfate hemihydrate, β-calcium sulfate hemihydrate, calcium sulfate in the form of anhydrite, slag sand, fly ash, fumed silica, blast furnace slag, natural pozzolanes, burnt oil shale, cement, and mixtures thereof, optionally wherein Portland cement is present in a proportion greater than 40% by weight based on the total amount of the inorganic binder.

16. A process (B) for the production of the polycondensate according to claim 12, wherein the following monomers are reacted: (Ia) a monomer comprising an aromatic moiety bearing a polyether side chain comprising alkylene glycol units, with the proviso that the number of ethylene glycol units in the side chain is from 9 to 50 and that the content of ethylene glycol units is higher than 80 mol % with respect to all alkylene glycol units in the polyether side chain, (IIa) a monomer comprising an aromatic moiety bearing at least one phosphoric acid monoester group and/or its salt, (IIb) a monomer comprising an aromatic moiety with 6 carbon atoms, bearing at least one hydroxy group attached to the aromatic moiety and (III) the monomer formaldehyde.

17. The polycondensate according to claim 1, wherein the molar ratio of (IIa):(IIb) is from 0.2 to 1.2.

Description

EXAMPLE 2

(1) The molar ratio of structural units of the general formula (I) to general formula (IIa) to general formula (IIb) is 1:2:1.52. The molecular weight of the structural unit (I) is 1,998 g/mol. The molecular weight of (IIa) is 216 g/mol, the molecular weight of (IIb) is 92.1 g/mol and the weight average molecular weight of the polycondensate M.sub.w is 17,020 g/mol (by GPC). It is noted that phenol sulfonic acid hydrolyses to phenol, which is then incorporated into the copolymer, therefore the molecular weight of phenol is considered as —[C.sub.6H.sub.3—O—H]—, which results in 92.1 g/mol.

(2) The mol number of methylene groups from formaldehyde is equal to the sum of the mol numbers of all aromatic structural units (I), (IIa) and (IIb). A structural unit (IV) is not present.
PD=M.sub.w/[(Σ.sub.i(n.sub.i.Math.M.sub.i))/(Σ.sub.in.sub.i)]

(3) In this case the PD value is 58.4=17,020 g/mol/[(1 mol.Math.1,998 g/mol+2 mol.Math.216 g/mol+1.52.Math.92.1 g/mol+4.52.Math.14 g/mol)/(1 mol+2 mol+1.52 mol+4.52 mol)].

EXAMPLE 3

(4) The molar ratio of structural units of the general formula (I) to general formula (IIa) to general formula (IIb) is 1:2:1.52. The molecular weight of the structural unit (I) is 1,998 g/mol. The molecular weight of (IIa) is 216 g/mol, the molecular weight of (IIb) is 92.1 g/mol (phenol was used) and the weight average molecular weight M.sub.w of the polycondensate is 19,660 g/mol (by GPC).

(5) The mol number of methylene groups from formaldehyde is equal to the sum of the mol numbers of all aromatic structural units (I), (IIa) and (IIb). A structural unit (IV) is not present.
PD=M.sub.w/[(Σ.sub.i(n.sub.i.Math.M.sub.i))/(Σ.sub.in.sub.i)]

(6) In this case the PD value is 67.5=19,660 g/mol/[(1 mol.Math.1,998 g/mol+2 mol.Math.216 g/mol+1.52 mol.Math.92.1 g/mol+4.52.Math.14 g/mol)/(1 mol+2 mol+1.52 mol+4.52 mol)].

EXAMPLE 5

(7) The molar ratio of structural units of the general formula (I) to general formula (IIa) to general formula (IIb) is 1:0.6:0.6. The molecular weight of the structural unit (I) is 748 g/mol. The molecular weight of (IIa) is 216 g/mol, the molecular weight of (IIb) is 92.1 g/mol (phenol sulfonic acid, which hydrolyses, was used) and the weight average molecular weight M.sub.w of the polycondensate is 9,860 g/mol (by GPC).

(8) The mol number of methylene groups from formaldehyde is equal to the sum of the mol numbers of all aromatic structural units (I), (IIa) and (IIb). A structural unit (IV) is not present.
PD=M.sub.w/[(Σ.sub.i(n.sub.i.Math.M.sub.i))/(Σ.sub.in.sub.i)]

(9) In this case the PD value is 45=9,860 g/mol/[(1 mol.Math.748 g/mol+0.6 mol.Math.216 g/mol+0.6 mol.Math.92.1 g/mol+2.2.14 g/mol)/(1 mol+0.6 mol+0.6 mol+2.2 mol)].

(10) The PD is a number without units and due to the fact that it is an average value, it can be also a broken number. Therefore it could be also called a value for the average of an assembly of polymers with the average molecular weight M.sub.w. Of course when looking at one specific polycondensate structure, only integral numbers are possible for the number of repeating units, because a broken number of monomers in a single polymer is not possible.

(11) Chemically, the PD value is an indicator of how many units (I), (IIa), (IIb), (III) and optionally (IV) are present in the polycondensate on average. In particular the PD value indicates the backbone length of the polycondensate.

(12) It has been found that shorter polyether side chain lengths contribute to the good rheological behaviour of concrete prepared with the polycondensates according to this invention. In particular low plastic viscosities of the concrete produced with the polycondensates can be obtained. Too short side chains become less economically interesting, as the dispersion effect decreases and the dosage needed for obtaining a certain level of workability (e.g. slump in the concrete test) increases.

(13) Preferable are polycondensates according to this invention in a formulation together with further dispersants selected from the group of a) sulfonated melamine-formaldehyde condensates, b) lignosulfonates, c) sulfonated ketone-formaldehyde condensates, d) sulfonated naphthalene-formaldehyde condensates (BNS), e) polycarboxylate ethers (PCE), f) non-ionic copolymers for extending workability to a cementitious mixture containing hydraulic cement and water, wherein the copolymer comprises residues of at least the following monomers: Component A comprising an ethylenically unsaturated carboxylic acid ester monomer comprising a moiety hydrolysable in the cementitious mixture, wherein the hydrolysed monomer residue comprises an active binding site for a component of the cementitious mixture; and

(14) Component B comprising an ethylenically unsaturated, carboxylic acid ester or alkenyl ether monomer comprising at least one C.sub.2-4 oxyalkylene side group of 1 to 350 units or g) phosphonate containing dispersants according to the following formula
R—(OA).sub.n-N—[CH.sub.2—PO(OM.sub.2).sub.2].sub.2
whereby
R is H or a saturated or unsaturated hydrocarbon rest, preferably a C1 to C15 alkyl radical,
A is the same or different and independently from each other an alkylene with two to 18 carbon atoms, preferably ethylene and/or propylene, most preferably ethylene,
n is an integer from 5 to 500, preferably 10 to 200, most preferably 10 to 100 and
M is H, an alkali metal, ½ earth alkali metal and/or an amine and whereby any combination of the before standing further dispersants a) to g) is possible.

(15) The polycondensates according to this invention are dispersants for inorganic binders, especially for cementitious mixtures like concrete or mortar. It is possible to use the polycondensates according to this invention also in a formulation with further dispersants for inorganic binders, preferably dispersants a) to g) as mentioned in the before standing text.

(16) When the polycondensates according to this invention are present in a formulation together with further dispersants, preferably with at least one of the dispersants a) to g), it is preferable that the weight ratio, in terms of solid content, of the polycondensates according to this invention to the sum of the weights of at least one of the further dispersants is preferably higher than ¼, more preferably higher than ⅓, most preferably higher than ⅔.

(17) The dosage of the sum of the polycondensates according to this invention and the further dispersant(s) in weight % of cement is from 0.1 to 2%, preferably 0.2 to 1%.

(18) The a) sulfonated melamine-formaldehyde condensates, which can be used as dispersant in a formulation with the polycondensates according to this invention are of the kind frequently used as plasticizers for hydraulic binders (also referred to as MFS resins). Sulfonated melamine-formaldehyde condensates and their preparation are described in, for example, CA 2 172 004 A1, DE 44 11 797 A1, U.S. Pat. Nos. 4,430,469, 6,555,683 and CH 686 186 and also in Ullmann's Encyclopedia of Industrial Chemistry, 5.sup.th Ed., vol. A2, page 131, and Concrete Admixtures Handbook—Properties, Science and Technology, 2.sup.nd Ed., pages 411, 412. Preferred sulfonated melaminesulfonate-formaldehyde condensates encompass (greatly simplified and idealized) units of the formula

(19) ##STR00005##
in which n stands generally for 10 to 300. The molar weight is situated preferably in the range from 2500 to 80 000. An example of melaminesulfonate-formaldehyde condensates are the products sold by BASF Constructoin Solutions GmbH under the Melment® name. Additionally to the sulfonated melamine units it is possible for other monomers to be incorporated by condensation. Particularly suitable is urea. Moreover, further aromatic units as well may be incorporated by condensation, such as gallic acid, aminobenzenesulfonic acid, sulfanilic acid, phenolsulfonic acid, aniline, ammoniobenzoic acid, dialkoxybenzenesulfonic acid, dialkoxybenzoic acid, pyridine, pyridinemonosulfonic acid, pyridinedisulfonic acid, pyridinecarboxylic acid and pyridinedicarboxylic acid, for example.

(20) The b) lignosulfonates, which can be used as dispersant together with the polycondensates according to this invention in a formulation, are products which are obtained as by-products in the paper industry. They are described in Ullmann's Encyclopedia of Industrial Chemistry, 5.sup.th Ed., vol. A8, pages 586, 587. They include units of the highly simplified and idealizing formula

(21) ##STR00006##
where n stands generally for 5 to 500. Lignosulfonates have molar weights of between 2000 and 100 000 g/mol. In general they are present in the form of their sodium, calcium and/or magnesium salts. Examples of suitable lignosulfonates are the products from the Norwegian company Borregaard LignoTech that are sold under the Borresperse commercial designation.

(22) The c) sulfonated ketone-formaldehyde condensates, which can be used as dispersant together with the polycondensates according to this invention in a formulation, are products incorporating a monoketone or diketone as ketone component, preferably acetone, butanone, pentanone, hexanone or cyclohexanone. Condensates of this kind are known and are described in WO 2009/103579, for example. Sulfonated acetone-formaldehyde condensates are preferred. They generally comprise units of the formula (according to J. Plank et al., J. Appl. Poly. Sci. 2009, 2018-2024:

(23) ##STR00007##
where m and n are generally each 10 to 250, M is an alkali metal ion, such as Na.sup.+, and the ratio m:n is in general in the range from about 3:1 to about 1:3, more particularly about 1.2:1 to 1:1.2. Examples of suitable acetone-formaldehyde condensates are the products sold by BASF Construction Solutions GmbH under the Melcret K1L commercial designation. Furthermore, it is also possible for other aromatic units to be incorporated by condensation, such as gallic acid, aminobenzenesulfonic acid, sulfanilic acid, phenolsulfonic acid, aniline, ammoniobenzoic acid, dialkoxybenzenesulfonic acid, dialkoxybenzoic acid, pyridine, pyridinemonosulfonic acid, pyridinedisulfonic acid, pyridinecarboxylic acid and pyridinedicarboxylic acid, for example.

(24) The d) sulfonated naphthalene-formaldehyde, which can be used as dispersant together with the polycondensates according to this invention in a formulation are products obtained by sulfonation of naphthalene and subsequent polycondensation with formaldehyde. They are described in references including Concrete Admixtures Handbook Properties, Science and Technology, 2.sup.nd Ed., pages 411-413 and in Ullmann's Encyclopedia of Industrial Chemistry, 5.sup.th Ed., vol. A8, pages 587, 588. They comprise units of the formula

(25) ##STR00008##

(26) Typically, molar weights (M.sub.w) of between 1000 and 50 000 g/mol are obtained. Examples of suitable β-naphthalene-formaldehyde condensates are the BASF Construction Solutions GmbH products sold under the Melcret 500 L commercial designation.

(27) Furthermore, it is also possible for other aromatic units to be incorporated by condensation, such as gallic acid, aminobenzenesulfonic acid, sulfanilic acid, phenolsulfonic acid, aniline, ammoniobenzoic acid, dialkoxybenzenesulfonic acid, dialkoxybenzoic acid, pyridine, pyridinemonosulfonic acid, pyridinedisulfonic acid, pyridinecarboxylic acid and pyridinedicarboxylic acid, for example.

(28) The invention relates also to a process (A) for the production of a polycondensate according to this invention, wherein the following monomers are reacted in the presence of an acid catalyst

(29) (I) a monomer comprising an aromatic moiety bearing a polyether side chain comprising alkylene glycol units, with the proviso that the number of ethylene glycol units in the side chain is from 9 to 130 and that the content of ethylene glycol units is higher than 80 mol % with respect to all alkylene glycol units in the polyether side chain,
(IIa) a monomer comprising an aromatic moiety bearing at least one phosphoric acid monoester group and/or its salt,
(IIb) a monomer comprising an aromatic moiety with 6 carbon atoms, bearing at least one hydroxy group attached to the aromatic moiety and
(III) the monomer formaldehyde.

(30) The term “formaldehyde” comprises also oligomeric and polymeric precursors of formaldehyde, like for example trioxane and para-formaldehyde.

(31) The invention relates also to a process (B) for the production of a polycondensate according to this invention, wherein the following monomers are reacted

(32) (Ia) a monomer comprising an aromatic moiety bearing a polyether side chain comprising alkylene glycol units, with the proviso that the number of ethylene glycol units in the side chain is from 9 to 50 and that the content of ethylene glycol units is higher than 80 mol % with respect to all alkylene glycol units in the polyether side chain and monomers (IIa), (IIb) and (III), which are the same as mentioned in the process (A).

(33) Optionally aromatic monomers (IV) are used in each case of processes (A) and (B), which are different from the monomers (I), (IIa) and (IIb).

(34) The monomers (I), (IIa), (III) (preferably formaldehyde, trioxan or para formaldehyde) and (IV) have been already described in the before standing text.

(35) Preferably the process (A) and the process (B) for the production of a polycondensate according to this invention is done using one or more than one monomers (M-IIb) with a molar mass lower than 202 g/mol, more preferably lower than 182 g/mol. Preferably the solubility in water of the monomer (M-IIb) used in the process (A) or (B) is higher than 10 g/I, more preferably higher than 15 g/I, at 20° C., pH=4 and atmospheric pressure. Preferably the pH value for the polycondensation reaction is set to be lower than 1.

(36) The monomer (IIb) can be preferably selected from the group of substituted or unsubstituted phenol, catechol, hydrochinone, benzene 1,2,3 triol, alkyl substituted phenols, preferably methyl substituted phenol, like for example ortho cresol, meta cresol and para cresol, 4-hydroxy phenol sulfonic acid, 3-hydroxy phenol sulfonic acid, 2-hydroxy phenol sulfonic acid, 3,4,5-trihydroxybenzenesulfonic acid, 2,4,5-trihydroxybenzenesulfonic acid, phenol 2,4-disulfonic acid and 3,4-dihydroxybenzenesulfonic acid. Preferable are phenol, catechol, hydrochinone, benzene 1,2,3 triol, methyl substituted phenols, like for example ortho cresol, meta cresol and para cresol, 4-hydroxy phenol sulfonic acid, 3-hydroxy phenol sulfonic acid and 2-hydroxy phenol sulfonic acid.

(37) The acid catalyst can be selected from the group of strong mineral acids like sulfuric acid, HCl, or a sulfonic acid. Preferably the sulfonic acid is an alkylsulfonic acid and/or an aromatic sulfonic acid. More preferably the aromatic sulfonic acid bears at least one hydroxy group. Most preferable is a phenol comprising at least one hydroxy group and at least one sulfonic acid, in each case attached to the aromatic ring. For example, it can be selected from the group of 4-hydroxy phenol sulfonic acid, 3-hydroxy phenol sulfonic acid, 2-hydroxy phenol sulfonic acid, 3,4,5-trihydroxybenzenesulfonic acid, 2,4,5-trihydroxybenzenesulfonic acid, phenol 2,4-disulfonic acid and 3,4-dihydroxybenzenesulfonic acid. It is possible to use mixtures of the before mentioned acid catalysts. Preferable are 4-hydroxy phenol sulfonic acid and/or phenol 2,4-disulfonic acid. In particular, preferable is 2-hydroxy phenol sulfonic acid.

(38) It has been found that the sulfonic acid group can act as an acid catalyst during the polymerization reaction. The aromatic sulfonic acid bearing at least one hydroxy group can lose its sulfonic acid group in a hydrolysis reaction (small amounts of water are usually present in the reaction) in which sulfuric acid is formed and the sulfonic acid group at the aromatic ring is replaced by hydrogen. Analytical results of copolymers obtained with phenol sulfonic acids (phenols comprising at least one hydroxy group and at least one sulfonic acid) show that the element sulfur could no more be detected by elemental analysis, which hints to the before mentioned hydrolysis process.

(39) It should be pointed out that if the monomer (IIb) is a phenol comprising at least one hydroxy group and at least one sulfonic acid group, in each case attached to the aromatic ring, it is possible to do the polycondensation reaction without an extra addition of an (additional) acid catalyst, because the monomer (IIb) is acid enough to promote the polycondensation. One or more species of the before mentioned monomers can be used in the process.

(40) Preferable is a process in which the acid catalyst is present in the form of the monomer (IIb), which is a phenol comprising at least one hydroxy group and at least one sulfonic acid group, in each case attached to the aromatic ring.

(41) Advantage is that no separate acid catalyst is needed and that the catalyst is completely copolymerized into the copolymer. In contrast to the use of for example mineral acids no salts like for sodium sulfate are formed, when for example a sample produced with sulphuric acid is neutralized with sodium hydroxide. Phase separation problems (salt precipitation) in aqueous systems are common in such a case.

(42) Preferably the process for the production of a polycondensate according to this invention is characterized in that the temperature is in the range from 80 to 140° C., preferably 100 to 120° C. More preferably the process is done under an atmosphere of nitrogen. Preferably the process is done under addition of sulfuric acid. It is also preferable to use no mineral acids as a catalyst.

(43) The invention relates also to a building material mixture comprising one or more polycondensates according to this invention and one or more inorganic binders selected from the group of α-calcium sulfate hemihydrate, α-calcium sulfate hemihydrate, calcium sulfate in the form of anhydrite, slag sand, fly ash, fumed silica, blast furnace slag, natural pozzolanes, burnt oil shale and/or, (Portland) cement, preference being given to the presence of (Portland) cement with a proportion greater than 40% by weight based on the total amount of the inorganic binder.

(44) The dosage of the polycondensates according to this invention is preferably in the range of 0.05 weight % to 1 weight %, with respect to the total amount of the inorganic binders. The dosage of the polycondensates according to this invention in concrete is more preferably in the range of 0.15 weight % to 0.5 weight %, with respect to the total amount of the inorganic binders. The building material mixtures can be for example concrete, mortar or grouts.

(45) The invention relates also to the use of the polycondensates according to this invention for the dispersion of inorganic binders, selected from the group of α-calcium sulfate hemihydrate, α-calcium sulfate hemihydrate, calcium sulfate in the form of anhydrite, slag sand, fly ash, fumed silica, blast furnace slag, natural pozzolanes, burnt oil shale and/or (Portland) cement, preference being given to the presence of (Portland) cement with a proportion greater than 40% by weight based on the total amount of the inorganic binder.

(46) The invention relates also to the use of the polycondensates according to this invention for increasing the strength development of concrete, in particular the strength development of concrete after 28 days.

(47) The invention relates also to the use of the polycondensates according to this invention for improving the slump-retention of concrete.

EXAMPLES

(48) General Phosphorylation Procedure:

(49) A reactor, equipped with heating and stirrer is charged with 127 g of polyphosphoric acid (specified to have 85% P.sub.2O.sub.5 content). The content is heated to 100° C. 1 mol of an alcohol (e.g. phenoxyethanol) is added to the stirred reaction mixture through a period of 3 hours. After the addition is finished, the reaction mix is stirred for an additional hour. The obtained reaction product mainly consists of the phosphoric acid monoester (e.g. phenoxyethanol phosphate) and can be used without further purification as starting material for the following polycondensation step.

(50) General Polycondensation Procedure:

(51) A pressure proof and corrosion resistant reactor (glass-lined steel, tantalized steel or hastelloy reactor), equipped with stirrer and temperature control is charged with below listed starting materials in the given order: 1. Poly(ethylenoxid)monophenylether (Ph-PEG), 2. Phosphorylated Phenoxyethanol (PPE) or phosphorylated Phenoxydiglycol (PPD), 3. Paraformaldehyde (PF) or Formalin 37%, 4. Water, 5. 2-Phenolsulfonic acid (PSA) 65%. For the samples 1*, 3, 4* and 6* sulfuric acid and/or phenol were added in accordance with table 1. Upon completion of the addition of the acid, the reaction mix is heated to 100-120° C. After 1 to 4 hours the polycondensation reaction is finished, water is added and the polycondensate is neutralized with NaOH to pH 6-8. Finally, the solid content of the product is adjusted with water to 32%.

(52) The molecular weights of the polymers were determined by using gel permeation chromatography method as described below.

(53) Column combination: OH-Pak SB-G, OH-Pak SB 804 HQ and OH-Pak SB 802.5 HQ by Shodex, Japan; eluent: 80 Vol.-% aqueous solution of HCO.sub.2NH.sub.4 (0.05 mol/I) and 20 Vol.-% acetonitrile; injection volume 100 μl; flow rate 0.5 ml/min. The exact amounts of the starting materials are given in table 1 and the reaction conditions are summarized in table 2.

(54) TABLE-US-00001 TABLE 1 Monomer composition of the polycondensates Ph-PEG Formalin Example MW PPE PPD PF 37% Water PSA 65% H.sub.2SO.sub.4 Phenol No. [D] [g] [mol] [g] [mol] [g] [mol] [g] [ml] [g] [g] [mol] [g] [g] [mol]  1* 2000 500 0.25 109.7 0.5 — — — 61.0 — — — 25.5 23.5 0.25 2 2000 500 0.25 109.7 0.5 — — 35.6 — — 100.5 0.38 — — — 3 2000 500 0.25 109.7 0.5 — — 35.6 — 30 — — 38.3 35.3 0.38  4* 750 600 0.8 104.8 0.48 — — 40.4 — 9.6 — — 24   — — 5 750 488 0.65 85.1 0.39 — — 45.2 — — 104.5 0.39 — — —  6* 5000 600 0.12 104.7 0.48 — — — 56.3 — — — 24.5 — — 7 5000 600 0.12 52.4 0.24 — — 24.7 — — 112.6 0.42 — — — 8 5000 600 0.12 52.4 0.24 — — 24.7 — — 112.6 0.42 — — — 9 5000 600 0.12 47.2 0.22 — — 24.7 — — 119.0 0.44 — — — 10  5000 600 0.12 36.7 0.17 — — 24.7 — — 131.9 0.49 — — — 11  5000 600 0.12 — — 44.1 0.17 24.7 — — 112.6 0.42 — — — 12  5000 600 0.12 104.7 0.48 — — 32.2 — — 112.6 0.42 — — — 13  5000 300 0.06 104.7 0.48 — — 23.3 — —  69.7 0.26 — — — (*= comparative example)

(55) TABLE-US-00002 TABLE 2 Reaction conditions and weight average molecular weight of the obtained polycondensates (*= comparative examples) Reaction Reaction Molecular weight Example temperature time Polycondensate Mw No. [° C.] [min] [D]  1* 100 300 10.740 2 100 240 17,020 3 100 210 19,660  4* 100 180 12,350 5 100 120 9,860  6* 120 240 29,060 7 100 240 39,920 8 110 100 39,440 9 110 100 41,130 10  110 100 43,890 11  110 100 42,560 12  100 60 22,300 13  100 60 27,860

(56) Given the results summarized in table 2, it can be concluded that the use of phenolsulfonic acid leads to a significant increase of the polycondensation speed.

(57) Considering the series of polycondensates with the same monomer (I) (Ph-PEG with 5,000 g/mol) it was found that, whereas in case of comparative example 6* 4 hours reaction time at a temperature of 120° C. were required in order obtain a polycondensate with a desired molecular weight of around 40,000 g/mol, a similar result was obtained in case of examples 7 to 13 at a lower reaction temperature and a significantly shorter reaction time.

(58) With respect to the series of polycondensates 1*, 2 and 3 with the same monomer (I) (Ph-PEG with 2,000 g/mol) it was possible to obtain at the same temperature of 100° C. a higher molecular weight (17,020 for sample 2 and 19,660 for sample 3), compared to the comparative example 1*, which resulted only in 10,740 g/mol. It is noted that the polycondensation time of 1* was even considerably longer (300 min) compared to samples 2 (240 min) and 3 (210 min).

(59) This invention therefore allows to significantly increase the throughput of a polycondensation plant with given specifications and it allows to reduce energy costs accordingly.

(60) Application Tests:

(61) Two different concrete mixes were used to evaluate the admixtures:

(62) Concrete mixture A: 1020 kg/m.sup.3 Crushed aggregate, 846 kg/m.sup.3 Sand, 350 kg/m.sup.3 portland cement (Bernburg CEM I 42.5 R), 50 kg/m.sup.3 Limestone powder; w/c=0.44)

(63) Concrete mixture B: 867 kg/m.sup.3 Crushed aggregate, 988 kg/m.sup.3 Sand, 380 kg/m.sup.3 portland cement (Bernburg CEM I 42.5 R), w/c=0.44

(64) The spread of concrete (15 shocks) was adjusted with the respective polycondensate samples (according to DIN EN 12350) to obtain values of 60±3 cm.

(65) The concrete flow test results are summarized in table 3. All polymers were formulated with 1% of a silicon-based defoamer in order to reduce the air entrainment into the concrete to less than 3%. Dosages are given as solid content by weight of cement content of the concrete mix.

(66) TABLE-US-00003 TABLE 3 Concrete flow test for concrete mixture A (*= comparative examples) Example Dosage Spread [cm] No. [%; b.w.o.c.] 5 min 15 min 30 min  1* 0.370 60.5 50.0 41.0 2 0.195 62.5 52.0 40.0 3 0.215 60.5 48.5 35.5  4* 0.370 60.0 57.5 51.5 5 0.320 60.0 58.5 52.5

(67) The concrete tests show that the admixtures according to this invention are able to provide equivalent flow properties of the fresh concrete, but at significantly reduced dosage compared to the comparative examples. Moreover, example 5 additionally provides an improved workability retention compared to the comparative example 4* at 13.5% reduced dosage.

(68) In a second test (Table 4) the strength development of the concrete was evaluated. Comparing Examples 7 to 13 with comparative example 6* reveals a higher dose efficiency of the inventive examples and a significantly increased compressive strength after 28 days:

(69) TABLE-US-00004 TABLE 4 Concrete compressive strength evaluation for concrete mixture B (*= comparative example), Compressive strength Density after Example Dosage Spread after 28 days 28 days No. [%; b.w.o.c.] [cm] [mPas] [kg/dm.sup.3]  6* 0.175 62.0 51.85 2.401  7 0.155 61.0 64.85 2.400  8 0.165 61.5 65.10 2.400  9 0.165 61.5 64.35 2.395 10 0.175 61.5 64.65 2.397 11 0.170 60.0 63.75 2.395 12 0.165 62.0 66.95 2.402 13 0.170 60.5 65.23 2.403