Mitigating the adverse effects of ettringite in inorganic binder compositions

Abstract

For improving the effectiveness of dispersants, in particular polycarboxylate ether dispersants, in inorganic binder compositions which form and / or contain ettringite and / or for reducing or inhibiting the adverse effect of ettringite on the effectiveness of dispersants in inorganic binder compositions, a polymer P is used, said polymer P comprising: a) at least one monomer unit M1 of formula I: CH2=CHNRCOR' (I), in which R and R' are independently of one another a hydrogen atom or a methyl group or R and R' together form an alkylene chain, so that a cyclic structure, in particular a 5-membered ring, is formed together with the N and C atoms to which R and R' are attached; and b) optionally at least one further monomer unit M2.

Description

[Technical Field]

[0001] The present invention relates to the use of polymers for improving the effectiveness of dispersants, in particular polycarboxylate ether-based dispersants, in inorganic binder compositions that form and / or contain ettringite and / or for reducing or inhibiting the adverse effect of ettringite on the effectiveness of the dispersants in inorganic binder compositions. [Background technology]

[0002] Dispersants or superplasticizers are used in the construction industry as plasticizers or water-reducing agents for inorganic binder compositions, such as concrete, cement mortar, plaster, or lime mortar. Dispersants are generally organic polymers that are added to the mixing water and mixed with the binder composition in solid form. In this way, it is possible to advantageously modify both the consistency of the binder composition during processing and its properties in the hardened state.

[0003] Known, particularly effective dispersants are, for example, polymers based on polycarboxylate ethers (PCE). This type of polymer has a polymer backbone with side chains attached to it. Corresponding polymers are described, for example, in EP 1 138 697 A1 (Sika AG).

[0004] Furthermore, EP 0 757 998 A2 (Showa Denko K.K.) describes water-soluble polymers based on N-vinylcarboxylic acid amides for imparting high fluidity to fresh mortar compositions, along with self-compacting properties and resistance to separation. These polymers can also be used together with water-reducing admixtures.

[0005] However, the effectiveness of a dispersant is determined by the properties of the dispersant and the specific components of the inorganic minder composition. For example, certain contaminants, such as swelling clays, even when present in very small amounts, can affect the effectiveness of PCE-based admixtures in the production of mortar or concrete.

[0006] The composition and hydration kinetics of the inorganic binder may also affect the effectiveness of the dispersant. For example, aluminate reactions, especially ettringite formation, are very important for the workability of cement-based materials. In particular, too rapid ettringite formation is known to have a negative effect on the rheology of the inorganic binder composition and the effectiveness of the dispersant.

[0007] To overcome this problem, hydration-controlling chemicals, such as retarders, are used. These include, for example, carboxylic acids, sugars, and phosphonates. EP 3 468 936 B1 (BASF SE) describes, for example, the use of special acid compounds in combination with organic carbonates to retard the hydration reaction of aluminate-containing clinker phases. This prevents premature setting of mortar and concrete pastes and ensures sufficient open time, allowing the paste to be processed as desired.

[0008] However, hydration control chemicals typically affect the hydration reaction as a whole, which can result in significantly slower setting of the inorganic binder composition, which can be undesirable for certain applications.

[0009] Therefore, there is a need for new and improved solutions that mitigate or overcome the above-mentioned drawbacks. Summary of the Invention [Problem to be solved by the invention]

[0010] One objective of the present invention is to provide materials and methods that can reduce or prevent problems associated with aluminate reactions, particularly ettringite formation, in inorganic bond compositions. Desirably, these solutions should reduce the adverse effect of rapid ettringite formation on the effectiveness of dispersants, particularly polycarboxylate ether-based dispersants. This should preferably minimize the impact of the hydration or setting time, respectively, of the inorganic bond composition. In particular, the materials or methods should be compatible with common additives or corresponding processes used in the production of inorganic bond compositions. In particular, the materials or methods should be compatible with lignosulfonates, gluconates, naphthalenesulfonates, sulfonated naphthalene-formaldehyde condensates, melamine sulfonates, vinyl copolymers, sulfonated vinyl copolymers, and / or polycarboxylates, particularly polycarboxylate ethers. In particular, the materials or methods should be compatible with PCE-based dispersants. [Means for solving the problem]

[0011] Surprisingly, it has been found that the above object of the present invention can be achieved by the features of claim 1. The core of the present invention therefore relates to the use of a polymer P for improving the effectiveness of a dispersant, in particular a polycarboxylate ether-based dispersant, in an inorganic binder composition that forms and / or contains ettringite and / or for reducing or inhibiting the adverse effects of ettringite on the effectiveness of the dispersant in the inorganic binder composition, said polymer P comprising: a) Formula I: CH2=CHNRCOR' (I) wherein R and R' are independently a hydrogen atom or a methyl group, or R and R' together form an alkylene chain, which together with the N atom and C atom to which R and R' are attached forms a cyclic structure, in particular a 5-membered ring. and at least one monomer unit M1 of the formula: b) optionally at least one further monomer unit M2, The use of a polymer P, comprising:

[0012] As shown, the polymer P of the present invention can significantly improve the effectiveness of dispersants, in particular polycarboxylate ether dispersants, in inorganic binder compositions that form and / or contain ettringite and / or can reduce or inhibit the adverse effects of ettringite on the effectiveness of dispersants in inorganic binder compositions.

[0013] Without wishing to be bound by theory, it is believed that polymer P adsorbs onto ettringite more readily than dispersants, such as polycarboxylate ether dispersants. Therefore, when using polymer P of the present invention, the adsorption capacity of ettringite for dispersants can be reduced or eliminated. Polymer P may also function as a co-surfactant with the dispersant, shielding the latter from ettringite. The exact mechanism may depend on the nature of the inorganic binder composition and the specific nature of the polymer P used. However, regardless of the mechanism, the effectiveness of the dispersant is less or not affected at all by ettringite.

[0014] The solution of the present invention has been found to be very robust, with polymer P alone having little or no effect on the hydration of the inorganic binder composition. In particular, polymer P has little effect on the hardening process of the inorganic binder composition.

[0015] Furthermore, the polymer P of the present invention itself has little effect on the slump flow of the inorganic binder composition, so the amount of dispersant used can be maintained within the established range, which in turn reduces the need for further adjustments to the formulation of the inorganic binder composition.

[0016] Furthermore, polymer P is fully compatible with each of the common additives used in the manufacture of inorganic binder compositions or the corresponding processes, such as dispersants, accelerators, retarders, shrinkage-reducing agents, and / or process chemicals typically used in mortar or concrete compositions.

[0017] Suitability is obtained for dispersants from, in particular, lignosulfonates, gluconates, naphthalenesulfonates, sulfonated naphthalene-formaldehyde condensates, melamine sulfonates, vinyl copolymers, sulfonated vinyl copolymers, and polycarboxylate ethers, the latter being of greatest interest in this regard, as they usually have a very pronounced dispersing effect.

[0018] Further aspects of the invention are the subject of the further independent claims. Particularly preferred embodiments of the invention are the subject of the dependent claims. DETAILED DESCRIPTION OF THE INVENTION

[0019] A first aspect of the present invention relates to the use of a polymer P for improving the effectiveness of a dispersant, in particular a polycarboxylate ether-based dispersant, in an ettringite-forming and / or containing inorganic binder composition and / or for reducing or inhibiting the adverse effect of ettringite on the effectiveness of the dispersant in the inorganic binder composition, said polymer P comprising: a) Formula I: CH2=CHNRCOR' (I) wherein R and R' are independently a hydrogen atom or a methyl group, or R and R' together form an alkylene chain, which together with the N atom and C atom to which R and R' are attached forms a cyclic structure, in particular a 5-membered ring. and at least one monomer unit M1 of the formula: b) optionally at least one further monomer unit M2, The present invention relates to the use of polymer P, which comprises

[0020] According to the invention, polymer P is used in particular to render ettringite inert to the adsorption of dispersants, in particular to the adsorption of polycarboxylate ether dispersants.

[0021] In the present context, a "polymer" is a substance comprising or consisting of at least two, in particular at least three, preferably at least five polymerized monomer units.

[0022] In particular, polymer P is used to improve the effectiveness of dispersants, in particular polycarboxylate ether dispersants, in inorganic binder compositions that form and / or contain ettringite, and / or to reduce or inhibit the adverse effect of ettringite on the effectiveness of dispersants in inorganic binder compositions, within 1 hour, in particular 30 minutes, in particular 10 minutes of mixing the inorganic binder composition with water, during which time early hydration of C3A-CaSO4 occurs, which is of utmost importance for rapid ettringite formation.

[0023] The term "dispersant effectiveness" refers to the ability of a powder, particularly a polycarboxylate ether-based dispersant, to improve the workability of an inorganic binder composition. An improvement in workability is an increase in workability. In particular, an improvement in workability can be measured as an increase in flow table spread according to standard EN 1015-3:2007, for example, immediately after mixing and / or after a specific time, such as 5, 30, 60, 90, and 120 minutes after mixing. A larger flow table spread corresponds to improved workability. This improvement can therefore be measured relative to the flow table spread of the same inorganic binder composition without the dispersant. An effective dispersant has a high ability to improve workability.

[0024] In other words, the present invention relates to the use of a polymer P as defined above in an inorganic binder composition comprising a dispersant, in particular a polycarboxylate ether based dispersant, for improving the effectiveness of a dispersant, in particular a polycarboxylate ether based dispersant, in said inorganic binder compositions which form and / or contain ettringite and / or for reducing or inhibiting the adverse effects of ettringite on the effectiveness of the dispersant in the inorganic binder composition, and for improving the workability of inorganic binder compositions which form and / or contain ettringite and / or for reducing or inhibiting the adverse effects of ettringite on the workability of inorganic binder compositions which comprise a dispersant, in particular a polycarboxylate ether based dispersant.

[0025] "Improvement of the effectiveness of the dispersant" particularly means an increase in the workability, in particular an increase in the flow table spread, of an inorganic binder composition comprising a dispersant, in particular immediately after mixing the inorganic binder composition with water. This improvement can be measured relative to the workability, in particular the flow table spread, of the same inorganic binder composition comprising a dispersant but not comprising the polymer P of the invention. In the context of the present invention, the flow table spread can be measured in accordance with standard EN 1015-3:2007.

[0026] The "detrimental effect of ettringite on the effectiveness of the dispersant" is a reduction in the flow table spread of the inorganic binder composition, especially immediately after mixing the inorganic binder composition with water.

[0027] As a benchmark for determining effectiveness and / or adverse effects, an inorganic binder composition can be used that does not contain the polymer P of the invention but that is otherwise identical in composition to the inorganic binder composition of the invention.

[0028] The present invention relates to a method for improving the workability of an inorganic binder composition that forms and / or contains ettringite and further contains a dispersant, in particular a polycarboxylate ether dispersant, comprising: (i) providing an inorganic binder composition; (ii) mixing a polymer with the inorganic binder composition, wherein the polymer P is: a) Formula I: CH2=CHNRCOR' (I) wherein R and R' are independently a hydrogen atom or a methyl group, or R and R' together form an alkylene chain, which together with the N atom and C atom to which R and R' are attached forms a cyclic structure, in particular a 5-membered ring. and at least one monomer unit M1 of the formula: b) optionally at least one further monomer unit M2, and The present invention also relates to a method, including:

[0029] When R and R′ together form an alkylene chain, the alkylene chain is preferably an alkylene chain having at least three methylene groups, in particular exactly three methylene groups, in other words, in the latter case R and R′ together represent a —CH—CH—CH— group or the monomer unit M is N-vinyl-2-pyrrolidone, respectively.

[0030] Regarding the structure of the polymer P, the monomer units M1 are preferably selected from N-vinylformamide, N-vinylacetamide, N-methyl-N-vinylformamide, N-vinyl-2-pyrrolidone, and / or N-methyl-N-vinylacetamide.

[0031] A particularly preferred monomer unit M1 comprises or consists of N-vinylformamide.

[0032] In another particularly preferred embodiment, the monomer unit M1 comprises or consists of N-vinyl-2-pyrrolidone.

[0033] In a highly preferred embodiment, the polymer P is a homopolymer of the monomer unit M1, in particular a homopolymer of N-vinylformamide or a homopolymer of N-vinyl-2-pyrrolidone.

[0034] Homopolymers have been found to be particularly useful in achieving the benefits of the present invention while at the same time being easily manufacturable.

[0035] However, in another preferred embodiment, the polymer P is a copolymer of at least one monomer unit M1 of formula I, in particular N-vinylformamide, and at least one further monomer unit M2.

[0036] In particular, at least one further monomeric unit M2 is different from the monomeric unit M1.

[0037] The at least one further monomer unit M2 is in particular chosen from vinyl-based, allylic, methallylic, acrylic, methacrylic, isoprenol ether monomers.

[0038] By using additional monomers M2, the properties of the polymer P can be further adjusted to suit the specific requirements of the inorganic binder composition.

[0039] Particularly preferably, the at least one further monomer unit M2 is selected from vinyl acrylic acid, methacrylic acid, acrylamide, vinylamine, vinyl alcohol, vinyl polyalkylene glycol, allyl polyalkylene glycol, methallyl polyalkylene glycol, isoprenol ether polyalkylene glycol, polyalkylene glycol acrylate, and / or polyalkylene glycol methacrylate.

[0040] In particular, at least one further monomer unit M2 has formula II: [ka] [where: R 1 , and R 2 is independently in each occurrence H or an alkyl group having 1 to 5 carbon atoms; R 3 is, independently in each occurrence, H, an alkyl group having 1 to 5 carbon atoms, preferably H or CH3, or a mixture thereof, or a group of formula -(CH2) m -[C=O] p -XR 4 is a group having the formula m=0, 1 or 2; p=0 or 1, X is independently at each occurrence -O-, -NH-, or -O-(CH2)4-O-; R 4 is the formula -[AO] n -R a is the basis of A=C2-C4-alkylene, and R a H, C1~C 20 -alkyl group, -cycloalkyl group, or -alkylaryl group; n = 2–250, especially 10–200] Includes the structure of

[0041] More particularly, R 1 =H or CH3, and R 2 =R 3 =H.

[0042] Advantageously at least 75 mol %, in particular at least 90 mol %, in particular at least 95 mol %, or at least 99 mol % of the total number of monomer units M2 have X groups -O- (=oxygen atom).

[0043] In a further advantageous embodiment, m=0, p=1, preferably X=—O—, in which case the copolymers can be prepared based on commercially available (meth)acrylic esters.

[0044] In another advantageous embodiment, m=0-2, p=0, preferably X=—O—, whereby the copolymers can be prepared based on commercially available vinyl ether, (meth)allyl ether, or isoprenyl ether monomers.

[0045] In one particularly advantageous embodiment, R 1 is a mixture of 40-60 mol % H and 40-60 mol % -CH3.

[0046] R in the monomer unit M2 with a side chain 4 The moiety is R in the monomer unit. 4 It particularly consists of poly(ethylene oxide) in an amount of at least 50 mol %, in particular at least 75 mol %, preferably at least 95 mol % or at least 99 mol %, based on the total number of moieties.

[0047] The proportion of ethylene oxide units, based on the total number of alkylene oxide units in the copolymer, is in particular greater than 75 mol %, in particular greater than 90 mol %, preferably greater than 95 mol %, in particular 100 mol %.

[0048] More particularly, R 4 is substantially free of hydrophobic groups, in particular alkylene oxides having 3 or more carbon atoms. This particularly means that the proportion of alkylene oxides having 3 or more carbon atoms, based on the total number of alkylene oxides, is less than 5 mol%, in particular less than 2 mol%, preferably less than 1 mol%, or even less than 0.1 mol%. In particular, alkylene oxides having 3 or more carbon atoms are not present, i.e., the proportion is 0 mol%.

[0049] R a is preferably H and / or a methyl group. Particularly preferably, A=C2-alkylene and R a is H or a methyl group.

[0050] More particularly, n=10 to 150, particularly n=15 to 100, preferably n=17 to 70, particularly n=19 to 45 or n=20 to 25.

[0051] In particular, the polymer P does not contain any monomer units containing sulfonic acid groups and / or salts thereof. In particular, the polymer P does not contain any monomer units containing the following structure: CH2=CHR 11 X 11 R 12 SO3X 12 [where R 11 =H or a methyl group; X 11 = CONH or COO; R 12 = a linear or branched alkylene group of 1 to 4 carbon atoms, and X 12 = hydrogen, alkali metal, ammonium salt, or organic ammonium salt] is not included.

[0052] The weight average molecular weight (M w The weight average molecular weight (M) is preferably 500 to 60,000 g / mol, particularly 1,000 to 50,000 g / mol, and particularly 2,000 to 15,000 g / mol. W ) is determined by gel permeation chromatography (GPC) using polyethylene glycol (PEG) as a standard.

[0053] In particular, polymer P may have, based on the total number of monomer units present in polymer P: a) 30 to 100 mol %, in particular 50 to 100 mol %, in particular 60 to 100 mol %, preferably 75 to 100 mol %, more preferably 80 to 100 mol %, even more preferably 90 to 100 mol % or 98 to 100 mol % of monomer units M1 of formula I, in particular N-vinylformamide and / or N-vinyl-2-pyrrolidone; b) optionally 0.1 to 70 mol %, in particular 1 to 50 mol %, in particular 5 to 40 mol %, preferably 10 to 25 mol % of at least one further monomer unit M2, It comprises or consists of:

[0054] In particular, the molar ratio of the monomeric unit M1 of formula I, in particular N-vinylformamide, is greater than the molar ratio of the at least one further monomeric unit M2, in particular the molar ratio of the monomeric unit M1 of formula I is equal to at least 1.1 times, in particular at least 1.5 times, in particular 2 times, for example at least 5 times the molar ratio of the at least one further monomeric unit M2.

[0055] In particular, the molar ratio of monomer unit M1 of formula I, in particular N-vinylformamide, to at least one further monomer unit M2 is preferably 1:1 to 100:1, preferably 1:1 to 90:1, more preferably 1:1 to 75:1, in particular 1.1:1 to 50:1, in particular 1.5:1 to 25:1.

[0056] The polymers are prepared in particular by free radical polymerization, for example by conventional free radical polymerization or by controlled free radical polymerization (also called living free radical polymerization), which polymerization techniques are well known to those skilled in the art.

[0057] In particular, the polymer P is used in liquid or solid form.

[0058] For example, the polymer P can be provided in the form of a liquid admixture, in particular dissolved or dispersed in a solvent, for example in water.

[0059] The polymer P can also be provided in the form of a solid admixture, for example in the form of a powder, optionally with further powders, for example carrier materials and / or filler materials.

[0060] The polymer P is preferably used in a proportion of 0.0001 to 10% by weight, in particular 0.001 to 5% by weight, in particular 0.005 to 2% by weight, in particular 0.01 to 0.2% by weight, for example 0.01 to 0.1% by weight, based on the total weight of the inorganic binder in the inorganic binder composition, which proportions provide the best mitigation of the adverse effects of ettringite and / or improvement of the effectiveness of the dispersant, while at the same time minimizing the effects of hydration of the inorganic binder composition with water as much as possible.

[0061] Polymer P is preferably used in combination with a polycarboxylate ether dispersant.

[0062] The proportion of polycarboxylate ether dispersant is in particular 0.0001 to 10% by weight, in particular 0.001 to 5% by weight, in particular 0.01 to 2% by weight, in particular 0.01 to 0.5% by weight, based on the total weight of the inorganic binder in the inorganic binder composition.

[0063] The weight ratio of polymer P to polycarboxylate ether dispersant is in particular 0.01 to 2, in particular 0.1 to 1, in particular 0.2 to 0.8, for example 0.4 to 0.7.

[0064] The polycarboxylate ether is preferably one of the following: a) a molar part of formula III: [ka] substructural unit S1, b) b molar parts of formula IV [ka] substructural unit S2, c) Formula of c molar parts (V): [ka] substructural unit S3, d) d molar parts of formula (VI) [ka] substructural unit S4, is a comb polymer CP having the substructural unit where: L is independently H + , an alkali metal ion, an alkaline earth metal ion, a divalent or trivalent metal ion, an ammonium ion, or an organic ammonium group; Each R u is, independently of the others, hydrogen or a methyl group; Each R v is, independently of the others, hydrogen or COOM, r=0, 1 or 2; t=0 or 1, G 1 and G 2 are independently C1 to C 20 -alkyl group, -cycloalkyl group, -alkylaryl group, or -(CH2) z -(O) z’ -[A'O] s -G 4 and where z=0, 1, 2, 3, or 4, z'=0 or 1, A'=C2-C4-alkylene, and G 4 H, C1~C 20 -alkyl group, -cycloalkyl group, or -alkylaryl group; s=2~250, G 3 are independently NH2, -NG 5 G 6 , -OG 7 NG 8 G 9 and Here, G 5 and G 6 is, independently, C1~C 20 -alkyl group, -cycloalkyl group, -alkylaryl group, or -aryl group; or a hydroxyalkyl group, or an acetoxyethyl group (CH3-CO-O-CH2-CH2-) or a hydroxyisopropyl group (HO-CH(CH3)-CH2-) or an acetoxyisopropyl group (CH3-CO-O-CH(CH3)-CH2-); or G 5 and G 6 together form a ring of which the nitrogen is part to form a morpholine or imidazoline ring; G 7 is a C2-C4 alkylene group, G 8 and G 9are independently C1 to C 20 represents an alkyl group, a cycloalkyl group, an alkylaryl group, an aryl group, or a hydroxyalkyl group; where a, b, c, and d represent the molar ratios of the respective substructural units S1, S2, S3, and S4; a / b / c / d=(0.1~0.9) / (0.1~0.9) / (0~0.8) / (0~0.8), In particular, a / b / c / d=(0.3~0.9) / (0.1~0.7) / (0~0.6) / (0~0.4), Preferably, a / b / c / d=(0.5 to 0.8) / (0.2 to 0.4) / 0 / 0, However, a+b+c+d=1.

[0065] A "comb polymer" is a polymer that includes a polymer backbone with side chains attached thereto.

[0066] The order of the substructural units S1, S2, S3, and S4 may be alternating, blocky, or random. One or more of the substructural units S1, S2, S3, and S4 may also form a gradient structure. In principle, further structural units may be present in addition to the substructural units S1, S2, S3, and S4. In particular, the order of the substructural units S1, S2, S3, and S4 in the comb polymer CP may be random or statistical.

[0067] Preferably, the proportion of substructural units S1, S2, S3 and S4 taken together is at least 50% by weight, in particular at least 90% by weight, most preferably at least 95% by weight of the total weight of the comb polymer CP.

[0068] Comb-shaped polymer CP, R v specifically represents hydrogen, and R u is preferably hydrogen and / or a methyl group.

[0069] Preferably, in the comb polymer CP, r=0 and t=1. Also advantageously, r=1-2 and t=0.

[0070] More particularly, in the comb polymer CP, R v is hydrogen and R u is a methyl group, r=1 to 2, and t=0.

[0071] G in comb-shaped polymer CP 1 and / or G 2 is, in each case independently, advantageously -[A'O] s -G 4 where s=8 to 200, in particular 20 to 70, and A' is a C2-C4-alkylene. Advantageously, therefore, z=z'=0.

[0072] Comb-shaped polymer CP, G 4 is independently in each occurrence preferably hydrogen or a methyl group.

[0073] Further particularly advantageous comb-shaped polymers CP are a)R u and R v The moiety is hydrogen, b) r=0, c) t=1, d) G 1 and G 2 is, in each case independently, -(CH2) z -(O) z’ -[A'O] s -G 4 , z=z'=0, s=20~70, A'=C2-alkylene; e)G 4 represents a methyl group, and / or f) a / b / c / d=(0.5~0.8) / (0.2~0.4) / (0.001~0.005) / 0. It is a comb-shaped polymer CP.

[0074] Similarly advantageous polymer CPs are a) t=0 and r=1 to 2; b) G 1 is, in each case independently, -(CH2) z-(O) z’ -[A'O] s -G 4 where z = z' = 0, s = 8 to 200, especially 20 to 70, c) G 4 represents hydrogen or a methyl group, in particular hydrogen, d) and / or A' is C2-C4-alkylene, in particular C2-alkylene; It is a polymer CP.

[0075] Weight average molecular weight (M W The weight average molecular weight (M) is in the range of, in particular, 5,000 to 150,000 g / mol, preferably 10,000 to 100,000 g / mol, and in particular 20,000 to 90,000 g / mol. W ) is determined by gel permeation chromatography (GPC) using polyethylene glycol (PEG) as a standard.

[0076] The preparation of comb polymers CP per se is well known to those skilled in the art. Corresponding superplasticizers or comb polymers CP are also commercially available from Sika Schweiz AG in the ViscoCrete® trade name series.

[0077] The term "inorganic binder" refers to a binder that reacts in the presence of water by hydration to form a solid hydrate or hydrate phase. This may be, for example, a hydraulic binder, a latent hydraulic binder, and / or a pozzolanic binder. Hydraulic binders are highly preferred. Hydraulic binders are capable of setting in water. However, in the case of inorganic binders, it may be advantageous to include other binders in addition to or apart from the hydraulic binder. These are in particular latent hydraulic binders and / or pozzolanic binders. Suitable latent hydraulic and / or pozzolanic binders are, for example, slag, fly ash, silica dust, and / or natural pozzolans. The inorganic binder in the inorganic binder composition comprises a substance capable of forming ettringite during hydration of the inorganic binder composition.

[0078] In particular, the inorganic binder in the inorganic binder composition includes an aluminate-containing phase and calcium sulfate. The aluminate-containing phase may be any of the preceding tricalcium aluminate (C3A), monocalcium aluminate (CA), tetraaluminate ferrate (C4AF), dodecalcium heptaaluminate (C4AF), and tetracalcium aluminate (C4AF). 12 A7) and / or yeelimite (C4A3$).

[0079] In particular, the inorganic binder comprises tricalcium aluminate and calcium sulfate. According to an embodiment, the inorganic binder comprises between 0.1 and 10 wt. %, preferably between 0.5 and 8 wt. %, more preferably between 1 and 7 wt. % of tricalcium aluminate, based on the total dry weight of the inorganic binder. According to an embodiment, the inorganic binder comprises between 0.1 and 5 wt. %, preferably between 0.5 and 3 wt. % of calcium sulfate, based on the total dry weight of the inorganic binder.

[0080] After mixing water is added to the inorganic binder, the aluminate-containing phases, such as tricalcium aluminate, and calcium sulfate undergo a hydration reaction to form ettringite. Ettringite is a hydrous calcium aluminum sulfate mineral. Ettringite has the formula: CaAl(SO)(OH) 12 It can be represented by 26H2O.

[0081] In particular, the inorganic binder comprises or consists of cement, in particular of type CEM I, CEM II, CEM III, CEM IV and / or CEM V (according to standard EN 197-1). These types of cement may contain tricalcium aluminate (C3A) and calcium sulfate as a minor component in proportions of up to 5% by weight. Therefore, ettringite formation usually occurs in such cements.

[0082] According to an embodiment, the inorganic binder forms at least 0.1 wt.-%, preferably at least 0.2 wt.-%, of ettringite relative to the total dry weight of the cured inorganic binder, the amount of ettringite being determined by TGA analysis as described in the experimental section.

[0083] In a preferred embodiment, the inorganic binder comprises at least 5% by weight, in particular at least 20% by weight, preferably at least 35% by weight, in particular at least 65% by weight, of a hydraulic binder, in particular cement, and optionally 5 to 95% by weight, in particular 5 to 65% by weight, in particular 15 to 35% by weight, of a latent hydraulic and / or pozzolanic binder, based on the total inorganic binder content.

[0084] According to an embodiment, the inorganic binder comprises clay (C), in particular calcined clay, limestone (LS), and Portland cement (PC) in the following weight ratios: PC:C is between 33:1 and 1:1, preferably between 8:1 and 1:1, C:LS is 10:1 to 1:50, preferably 10:1 to 1:33, more preferably 5:1 to 1:10, - PC:LS is 20:1 to 1:4, preferably 5:1 to 1:1.

[0085] In this context, clay refers to a solid material containing at least 30% by weight, preferably at least 35% by weight, and particularly at least 75% by weight of clay minerals, based on its dry weight. Such clay minerals preferably belong to the kaolin group (such as kaolinite, dickite, nacrite, or halloysite), the smectite group (such as montmorillonite, nontronite, or saponite), the vermiculite group, serpentine, palygorskite, sepiolite, chlorite, talc, pyrophyllite, mica (such as biotite, muscovite, illite, glauconite, celadonite, and phengite), or mixtures thereof. Clay minerals belonging to the kaolin group, particularly kaolinite, and mica, particularly muscovite and illite, and mixtures thereof, are particularly preferred. Clay minerals in this context may be any type of clay mineral, such as raw clay, low-temperature calcined clay, or high-temperature calcined clay. Raw clay is, for example, a clay mineral extracted from a quarry, optionally refined, and optionally dried. Low-temperature calcined clays are clays that have been heat-treated at temperatures between 500 and 1200°C. Such low-temperature calcination typically removes interlayer water and at least partially, preferably completely, dehydroxylates the clay. For example, low-temperature calcined clay minerals can be produced in a rotary kiln or a flash calciner. High-temperature calcined clays are clay minerals that have been heat-treated at temperatures above 1200°C, typically between 1300 and 1400°C. High-temperature calcined clays are typically crystalline or contain a large amount of crystalline phases, particularly mullite.

[0086] The clay in this context is preferably a low-temperature-calcined clay. Low-temperature-calcined clay is a clay material that has undergone a heat treatment at a temperature between 500 and 1200°C or a flash calcination process at a temperature between 800 and 1100°C. Suitable flash calcination processes are described, for example, in WO 2014 / 085538. Low-temperature-calcined clay is an anhydrous material. In this context, during clay calcination, the clay material is preferably dehydroxylated to an amorphous material while preventing the formation of crystalline high-temperature aluminosilicate phases such as mullite. Low-temperature-calcined clays, particularly low-temperature-calcined kaolinite, are generally amorphous and have a much larger specific surface area than the original clay and possess pozzolanic activity. According to a particularly preferred embodiment of the present invention, the calcined clay is metakaolin. Metakaolin is a material obtained by low-temperature calcination of kaolinite or a kaolinite-rich mineral, e.g., having a kaolinite content of at least 30% by weight, preferably at least 35% by weight, based on its dry weight. Calcination temperatures for producing metakaolin are typically in the range of 500 to 900°C.

[0087] According to an embodiment, the inorganic binder consists of at least 65% by weight, preferably at least 80% by weight, more preferably at least 92% by weight of clay, limestone and Portland cement, in each case relative to the total dry weight of the inorganic binder.

[0088] According to an embodiment of the present invention, the inorganic binder comprises: a) 25 to 100 parts by mass of Portland cement (PC), b) 3 to 50 parts by weight of clay (C), in particular calcined clay, in particular metakaolin, c) 5 to 100 parts by mass of limestone (LS); Contains a mixture of

[0089] According to a further embodiment of the present invention, the inorganic binder is a) 5 to 95% by weight, preferably 6 to 80% by weight, of a slag-based binder, a1) at least one steel slag, preferably granulated blast furnace slag; a2) optionally a second slag different from a1), preferably basic oxygen furnace slag; a3) optionally latent hydraulic and / or pozzolanic additives, preferably silica dust, natural pozzolana, fly ash, and / or burnt oil shale; a slag-based binder comprising or consisting of b) 5 to 95% by weight, preferably 20 to 94% by weight, of at least one co-binder different from the slag-based binder a) and selected from the group consisting of Portland cement, calcium aluminate cement and / or calcium sulfoaluminate cement, in particular Portland cement, c) 0 to 10% by weight of additives, in particular stimulants; Contains a mixture of

[0090] An "inorganic binder composition" is a composition comprising an inorganic binder and, optionally, one or more further components, particularly as described above. The inorganic binder composition can be in the form of a dry composition or in the form of a composition mixed with water.

[0091] The inorganic binder composition may further comprise aggregate. The term "aggregate" includes all types of mortar and / or concrete aggregates. In particular, the aggregate may be 2.2-3 kg / dm 3 It is characterized by a density of

[0092] In particular, the aggregates include stone, gravel, sand, ground quartz, and / or limestone, but the aggregates can also comprise or consist of lightweight aggregates, in particular expanded clay or polystyrene, or heavy aggregates, such as barite, iron ore, etc.

[0093] In particular, the aggregate has a particle size of at least 0.125 mm or at least 0.250 mm. Preferably, the aggregate has a particle size of at most 125 mm or at most 32 mm. In particular, the aggregate has a particle size of 0.125 to 125 mm, in particular 0.125 to 32 mm, in particular 0.125 to 16 mm, for example 0.125 to 8 mm or 0.125 to 5 mm.

[0094] In the present context, particle size is determined by sieve analysis, in particular using sieves characterized by square openings. In particular, particle size is expressed by the size of the opening of the test sieve through which the relevant granules or particles just pass.

[0095] Furthermore, the inorganic binder composition may contain additives selected in particular from additives conventionally used in mortar or concrete compositions. In particular, the additives are selected from plasticizers, accelerators, corrosion inhibitors, retarders, shrinkage reducing agents, antifoaming agents, and / or foaming agents. In this regard, the additives are chemically and / or physically different from the dispersant and the polymer P.

[0096] The proportion of the additive is in particular 0.0001 to 10% by weight, in particular 0.001 to 5% by weight, in particular 0.01 to 2% by weight, based on the total weight of the inorganic binder in the inorganic binder composition.

[0097] In particular, the inorganic binder composition is a grout, mortar or concrete composition.

[0098] To prepare the inorganic binder composition, mixing water is added.

[0099] Preferably, the ratio of water to inorganic binder in the inorganic binder composition is in particular 0.25 to 0.8, in particular 0.3 to 0.6, for example 0.4 to 0.5.

[0100] In particular, the polymer P is added to the inorganic binder composition before the mixing water is added to the inorganic binder composition. In this regard, the polymer P is preferably homogeneously mixed with the other components of the inorganic binder composition. In this case, for example, the polymer P can be added in the form of a solid or liquid admixture, as described above.

[0101] This ensures that the polymer P is present in the inorganic binder composition when the hydration reaction and the formation of ettringite begins.

[0102] In particular, the polymer P is added to the inorganic binder composition before adding the dispersant.

[0103] In particular, the polymer P is added to the inorganic binder during its production, in particular by inter-grinding the polymer P and the inorganic binder, for example in a cement mill. In this regard, the proportion of polymer can be adapted to the nature of the inorganic binder, for example the proportion of sulfate and / or aluminate phases in the inorganic binder.

[0104] In particular, the polymer P can be provided as an admixture comprising the polymer P, the dispersant and, optionally, further additives, which simplifies the use of the polymer P since the ratios can be fixed.

[0105] However, the polymer P can be added independently of further additives or components of the inorganic binder composition, which allows more flexibility since the proportion of polymer P can be adjusted as desired independently of the other components or additives. In this regard, for example, the polymer P can be added together with and / or after the dispersant.

[0106] A further aspect of the present invention is directed to an inorganic binder or inorganic binder composition comprising a polymer P as described above and a dispersant. In particular, the inorganic binder and inorganic binder composition are as defined above. In particular, the inorganic binder or inorganic binder composition comprises substances capable of forming ettringite during hydration of the inorganic binder composition, in particular tricalcium aluminate (C3A) and calcium sulfate.

[0107] According to a particular embodiment, the inorganic binder composition comprising an inorganic binder, a polymer P and water has a content of solubilized aluminate and solubilized sulfate, in particular a content of solubilized aluminate and solubilized sulfate such that the molar ratio of aluminate:sulfate is about 2:3.

[0108] Another aspect is directed to a kit of parts comprising the aforementioned polymer P and a dispersing agent for inorganic binder compositions, in particular a polycarboxylate ether, which dispersing agent is chemically and / or structurally different from the polymer P. In particular, the kit of parts is present as a one-, two- or multi-component admixture. In a two- or multi-component admixture, the polymer P and the dispersing agent are preferably provided as spatially separated components.

[0109] A further aspect is directed to a method, in particular a method for plasticizing an inorganic binder composition, comprising the step of adding to the inorganic binder composition the aforementioned polymer P and the aforementioned dispersing agent for the binder composition.

[0110] Further advantageous embodiments and feature combinations of the present invention will become apparent from the following exemplary embodiments and the claims as a whole.

[0111] Representative Embodiments Production of polymer P Poly(N-vinylformamide) and polyvinylpyrrolidone were purchased and used as received.

[0112] Polymers P1 and P2 were prepared according to the following general procedure.

[0113] Comonomer 1 (type and amount listed in Table 1 below) was charged to a glass reactor equipped with a thermometer, stirrer, dropping funnel, and reflux condenser and diluted with water in an amount three times the initial weight of comonomer 1. The resulting mixture was heated to 80°C. While heating, a gentle stream of inert gas (N2) was passed through the stirred solution for the remaining reaction time. 3.5 wt% (based on comonomer 1) of 4-cyano-4-(thiobenzoylthio)pentanoic acid was added. After the above material was completely dissolved, 0.7 wt% (based on comonomer 1) of azobisisobutyronitrile was added. The conversion was then periodically determined by HPLC. As soon as the conversion based on comonomer 1 exceeded 85%, comonomer 2 was added to the reaction mixture. After 2.5 hours, all of comonomer 2 had reacted as determined by HPLC. A polymer with a block-like distribution of monomer units was obtained. A reddish polymer solution was obtained.

[0114] Polymers P3, P4, and P5 were prepared by the following general procedure.

[0115] A glass reactor equipped with a thermometer, a stirrer, a dropping funnel, and a reflux condenser was charged with comonomer 1 (type and amount as set forth in Table 1 below) and an amount of water equal to the initial weight of comonomer 1. 0.8 wt. % Fe(II)SO4 * A 10% aqueous solution of 7H2O and 0.8 wt% sodium hypophosphite (each based on comonomer 1) were added. Next, at a temperature of 25-50°C, 1.3 wt% (based on comonomer 1) of a 35% aqueous solution of hydrogen peroxide, the respective types and amounts of comonomer 2 and optional comonomer 3, and 0.7 wt% (based on comonomer 1) of a 5% aqueous solution of the initiator sodium hydroxymethylsulfinate were added dropwise over 15 minutes via separate feeds with stirring. The reaction solution was cooled to prevent the temperature from rising above 50°C. The reaction mixture was then further stirred until peroxide was no longer detectable. Polymers with a random distribution of monomer units were obtained. Each polymer was obtained as an aqueous solution.

[0116] [Table 1]

[0117] Mortar mixture The effectiveness of the polymer P according to the invention was tested in different mortar compositions.

[0118] The first mortar mixture MH was based on a high ettringite forming inorganic binder. The second mortar mixture ML was based on a low ettringite forming binder. The dry compositions of the mortars are shown in Table 2.

[0119] [Table 2]

[0120] For the mixing of the mortar mixtures, the binder and sand were dry mixed in a Hobart mixer for 1 minute. Within 30 seconds, mixing water (225 g; w / b = 0.5) was added and mixed for a further 2.5 minutes. In each case, the total wet mixing time was 3 minutes.

[0121] Depending on the individual experiment, polymer P and / or dispersant were added with the mixing water as shown in Tables 3 and 4.

[0122] test To investigate the usefulness of polymer P, the respective flow table spread (FTS) was measured 5, 30, 60, 90 and 120 minutes after mixing, according to the standard EN 1015-3:2007.

[0123] Furthermore, heat flow calorimetry was performed on samples of the mortar compositions by isothermal calorimetry at 23°C. The calorimetry curves represent the energy released in the mortar mixture specimens as a function of time (h) in units of (W / g inorganic binder). The heat evolution is due to the exothermic reaction of silicate phases in the inorganic binder with water. The maximum value of the calorimetric curves can be correlated with the strength development in the cement, i.e., a maximum occurring at an earlier time indicates an earlier development of early strength in the component.

[0124] Ettringite formation was measured as follows: Cement with a known content of C3A (tricalcium aluminate) was mixed with water to a water to cement weight ratio of 0.35. A superplasticizer (Viscocrete®, available from Sika Schweiz AG) was added along with the mixing water. Tests were performed with and without polyvinylformamide. Ten minutes after the addition of the mixing water, the hydration reaction was stopped by adding isopropanol, and the samples were then thoroughly dried. Thermogravimetric analysis (TGA) was performed on the dried samples. The mass loss between 70 and 100 °C corresponds to the amount of ettringite formed.

[0125] In the following, experiments R1 to R7 are controls not according to the present invention, and experiments A1 to A9 and B1 to B2 are according to the present invention. [Example]

[0126] Example 1 In Example 1, different polymers P were evaluated in mortar mixtures. The results of the different experiments carried out are shown in Tables 3 and 4.

[0127] [Table 3]

[0128] Experiment R1 shows that the initial flow (5 minutes after preparation) of the mortar composition without any dispersant is somewhat smaller, i.e., 146 mm, and the silicate hydration peak is at about 510 minutes. When adding a dispersant without the polymer P of the present invention (see experiment R2), the initial flow can be improved to 185 mm, while the silicate hydration peak shifts to a later time.

[0129] Addition of the polymer P of the present invention without any dispersant (see experiment R3) does not improve the flow of the mortar composition and only shifts the silicate hydration peak to a slightly later time. It can therefore be concluded that the polymer P itself does not have a dispersing effect and has little effect on the setting time.

[0130] However, when a polymer and a dispersant are used in combination (Experiments A1 to A3), the flow is always significantly improved compared to Reference Example R2, while the hardening is very slightly slower. It can therefore be concluded that the polymer P of the present invention can indeed improve the effectiveness of dispersants in inorganic binder compositions to form ettringite, or can mitigate the adverse effect of ettringite on the effectiveness of the dispersant.

[0131] While Experiments R1-R3 were all conducted using mortar mixtures that formed somewhat more ettringite, Experiment R4 used mortar mixture ML, which had an inorganic binder containing less aluminate. This resulted in much better flow, even without dispersants, comparable to the flow of Experiment R2. However, to achieve these results, the entire mortar formulation had to be modified. Therefore, binders from different plants, different regions, different types, or even different production lots can easily vary in composition and therefore produce different amounts of ettringite formation. This can have an impact on the stability of the dispersants. The solution of the present invention is therefore much more flexible. In particular, it can be used to solve problems related to ettringite formation in virtually any type of mortar or concrete composition, even when the binder composition varies between the same plant in the form of different production lots.

[0132] [Table 4]

[0133] Comparison of experiments A5-A9 with R5 shows that copolymers containing monomer units derived from vinylpyrrolidone or N-vinyl-formamide do improve the flow of mortar compositions in the presence of dispersants, with the silicate hydration peak only shifting slightly to later times.

[0134] Example 2 In Example 2, polymer P was evaluated in mixtures that formed low or high amounts of ettringite. In these experiments, two different types of cement were used. Cement A was CEM II / A-LL 42.5R with a content of 5.70 wt.% C3A and 4.5 wt.% sulfate. Cement B was CEM I 42.5R SR (sulfate resistant) with a content of 0.60 wt.% C3A and 4.40 wt.% sulfate. The results of the experiments are shown in Table 5.

[0135] [Table 5]

[0136] A comparison of R6 and B1 shows that the addition of polymer P increases FTS when a significant amount of ettringite is formed. A comparison of R7 and B2 shows that the increase in FTS is much smaller when only a small amount of ettringite is formed. It can therefore be concluded that polymer P of the present invention is particularly effective in reducing or suppressing the adverse effects of ettringite.

[0137] It will be recognized by those skilled in the art that the present invention can be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The presently disclosed embodiments are therefore considered in all respects to be illustrative and not restrictive.

Claims

1. 1. Use of a polymer P for improving the effectiveness of a dispersant, in particular a polycarboxylate ether-based dispersant, in an inorganic binder composition that forms and / or contains ettringite and / or for reducing or inhibiting the adverse effect of ettringite on the effectiveness of the dispersant in the inorganic binder composition, said polymer P comprising: a) Formula I: CH ２ =CHNRCOR’ (I) wherein R and R′ are independently a hydrogen atom or a methyl group, or R and R′ together form an alkylene chain, so that a cyclic structure, in particular a 5-membered ring, is formed together with the N atom and the C atom to which R and R′ are attached. and at least one monomer unit M1 of the formula: b) optionally at least one further monomer unit M2, Use of polymer P, comprising:

2. 2. The use according to claim 1, wherein the monomer unit M1 is N-vinylformamide and / or N-vinyl-2-pyrrolidone.

3. 3. The method according to claim 1, wherein the polymer P is a homopolymer of N-vinylformamide or a homopolymer of N-vinyl-2-pyrrolidone.

4. 3. The use according to claim 1, wherein the polymer P is a copolymer of at least one monomer unit M1 of formula I, in particular N-vinylformamide, and at least one further monomer unit M2.

5. 5. The use according to any one of claims 1 to 4, wherein the at least one further monomer unit M2 is selected from vinylic, allylic, methallylic, acrylic, methacrylic, isoprenol ether monomers.

6. 6. The use according to any one of claims 1 to 5, wherein the at least one further monomer unit M2 is selected from vinyl acrylic acid, methacrylic acid, acrylamide, vinylamine, vinyl alcohol, vinyl polyalkylene glycol, allyl polyalkylene glycol, methallyl polyalkylene glycol, isoprenol ether polyalkylene glycol, polyalkylene glycol acrylate, and / or polyalkylene glycol methacrylate.

7. The at least one further monomer unit M2 is represented by formula I 【Chemical 1】 [where: R １ , and R ２ is independently in each occurrence H or an alkyl group having 1 to 5 carbon atoms; R ３ is, independently in each occurrence, H, an alkyl group having 1 to 5 carbon atoms, preferably H or CH ３ , or mixtures thereof, or the formula -(CH ２ ) ｍ -[C=O] ｐ -X-R ４ is a group having the formula m=0, 1 or 2; p=0 or 1; X, independently in each occurrence, is —O—, —NH—, or —O—(CH ２ ) ４ -O-, R ４ is represented by the formula -[AO] ｎ -R ａ is the basis of A=C ２ ~C ４ - alkylene, and R ａ is H, C １ ~C ２０ -alkyl group, -cycloalkyl group, or -alkylaryl group, n=2 to 250, particularly 10 to 200. The use according to any one of claims 1 to 6, comprising the structure

8. The weight average molecular weight (M ｗ 8. Use according to claim 1 , wherein the molecular weight of the polymer is from 500 to 60,000 g / mol, in particular from 2,000 to 50,000 g / mol, in particular from 2,000 to 15,000 g / mol.

9. The polymer P has a molecular weight of 1,000,000, based on the total number of monomer units present in the polymer P: a) 30 to 100 mol %, in particular 50 to 100 mol %, in particular 60 to 100 mol %, preferably 75 to 100 mol %, more preferably 80 to 100 mol %, even more preferably 90 to 100 mol % or 98 to 100 mol % of monomer units M1 of formula I as defined above, in particular N-vinylformamide; b) optionally 0.1 to 70 mol %, in particular 1 to 50 mol %, in particular 5 to 40 mol %, preferably 10 to 25 mol % of said at least one further monomer unit M2, The use according to any one of claims 1 to 8, comprising:

10. Use according to any one of claims 1 to 9, wherein the molar ratio of the monomer unit M1 of formula I, in particular N-vinylformamide, to the at least one further monomer unit M2 is from 1:1 to 100:1, preferably from 1:1 to 90:1, more preferably from 1:1 to 75:1, in particular from 1.1:1 to 50:1, in particular from 1.5:1 to 25:

1.

11. Use according to any one of the preceding claims, wherein the polymer P is used in a proportion of 0.0001 to 10% by weight, in particular 0.001 to 5% by weight, in particular 0.005 to 2% by weight, in particular 0.01 to 0.2% by weight, for example 0.01 to 0.1% by weight, based on the total weight of the inorganic binder in the inorganic binder composition.

12. Use according to any one of claims 1 to 11, wherein the polymer P is used in combination with a polycarboxylate ether dispersant.

13. Use according to any one of the preceding claims, wherein the polymer P is added to the inorganic binder or to the inorganic binder composition before mixing water is added to the inorganic binder composition.

14. The inorganic binder in the inorganic binder composition is tricalcium aluminate (C ３ The use according to any one of claims 1 to 13, comprising A) and calcium sulfate.

15. Substances capable of forming ettringite during hydration of the inorganic binder composition, in particular tricalcium aluminate (C ３ A) and calcium sulfate, further comprising a polymer P as defined in any one of claims 1 to 14 and optionally a polycarboxylate ether dispersant.

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