OLIGOMERIC DISPERSANT
FIELD OF THE INVENTION
The present invention is directed to an oligomeric dispersant. More particularly, the present invention is directed to an oligomeric dispersant for cementitious particles. Specifically, the present invention is directed to a reaction product of a moiety that adsorbs on to a particle to be dispersed, a moiety that provides the dispersing capability, and an optional moiety that is disposed between the other moieties to provide connections between the other moieties.
BACKGROUND OF THE INVENTION
A cementitious mixture refers to pastes, mortars, and concrete compositions comprising a hydraulic cement binder. Pastes are defined as mixtures composed of a hydraulic cement binder, either alone or in combination with pozzolans such as fly ash, silica fume, or blast furnace slag, and water. Mortars are defined as pastes that additionally include fine aggregate. Concretes additionally include coarse aggregate. These compositions may additionally include other admixtures such as set retarders, set accelerators, defoaming agents, air-entraining or air-detraining agents, corrosion inhibitors, water-reducing agents, pigments, and any other admixture that does not adversely affect the advantageous results obtained by the present invention.
Dispersants are substances that improve the flow characteristics of a cement slurry by breaking up cement agglomerates and freeing the water, thus giving slurries of lower viscosity and allowing desirable flow conditions to be obtained at lower pump pressures. (See, for example, V.S. Ramachandran, Concrete Admixtures Handbook:
Properties, Science, and Technology, Noyes Publications (Second Edition, 1995)).
Dispersants have been used in the construction industry to disperse cementitious mixtures. Dispersants such as sulfonated melamine formaldehyde condensate (SMF), sulfonated naphthalene formaldehyde condensate (BNS), and lignosulfonates are
commonly used as dispersants. However, in order to achieve a desired level of concrete workability or water reduction, more of such compounds than is desirable need be added. In addition, these materials do not achieve full range (Type A to Type F) water-reducing capability, as defined in ASTM C494. For example, lignosulfonates achieve only a low to mid-range (5-12%) water reduction.
Dispersants are a necessary component in high strength and high durability concretes. Due to the requirement for the use of low amounts of water in high performance concretes, high dispersant amounts are sometimes necessary to achieve workable concretes. High BNS levels can lead to undesirable retardation of set and may not provide the required workability retention over time.
It is desirable to provide a material that is several times more efficient as a cement or concrete dispersant than the traditional materials such as lignosulfonates, BNS and SMF. Improving efficiency reduces the amount of material required to achieve a desired level of concrete workability or water reduction. With respect to the presently- used dispersants, lignosulfonates, BNS and SMF, it is also desirable to improve slump retention while maintaining normal setting characteristics. Providing a dispersant with full range (Type A to F) water-reducing capability is also a desirable characteristic.
One improvement in the prior art was the introduction of polycarboxylate dispersants. Polycarboxylate dispersants are structured with a polymeric backbone, such as a carbon chain backbone, with pendant moieties. The pendant moieties provide the dispersing capabilities of the molecule. For example, poly acrylic acid has carboxylic groups attached to the backbone. In addition, side chain moieties such as polyoxyalkylenes can be attached to the carboxylic groups to provide further dispersing capabilities. These dispersants operate by surrounding a particle to be dispersed, and then repulsion forces between each polymer chain keeps the particles apart and the dispersion more fluid.
It is an object of the invention to provide oligomeric dispersants for dispersing cementitious particles, wherein the dispersant adsorbs on to the particle to be dispersed.
SUMMARY OF THE INVENTION
The present invention provides a cementitious formulation comprising a hydraulic cement and a dispersant comprising a reaction product of component A, optionally component B, and component C; wherein each component A is independently a nonpolymeric, functional moiety capable of adsorbing on to a cementitious particle, and contains at least one residue derived from a first component selected from the group consisting of phosphates, phosphonates, phosphinates, hypophosphites, sulfates, sulfonates, sulfinates, alkyl trialkoxy silanes, alkyl triacyloxy silanes, alkyl triaryloxy silanes, borates, boronates, boroxines, phosphoramides, amines, amides, quaternary ammonium groups, carboxylic acids, carboxylic acid esters, alcohols, carbohydrates, phosphate esters of sugars, borate esters of sugars, sulfate esters of sugars, salts of any of the preceding moieties, and mixtures thereof; wherein component B is an optional moiety, where if present, each component B is independently a nonpolymeric moiety that is disposed between the component A moiety and the component C moiety, and is derived from a second component selected from the group consisting of linear saturated hydrocarbons, linear unsaturated hydrocarbons, alicyclic hydrocarbons, saturated branched hydrocarbons, unsaturated branched hydrocarbons, aryl, phosphoester, nitrogen-containing compounds, and mixtures thereof; and wherein component C is at least one moiety that is a linear or branched water-soluble nonionic polymer substantially non-adsorbing to cement particles, and is selected from the group consisting of poly(oxyalkylene glycol), poly(oxyalkylene amine), poly(oxyalkylene diamine), monoalkoxy poly(oxyalkylene amine), monoaryloxy poly(oxyalkylene amine), monoalkoxy poly(oxyalkylene glycol), monoaryloxy poly(oxyalkylene glycol), poly(vinyl pyrrolidones), poly (methyl vinyl ethers), poly (ethylene imines), poly (aery lamides), polyoxazoles, and mixtures thereof;
wherein if the A moiety contains any phosphate, phosphonate, phosphinate, or hypophosphite residue the molecule is further characterized by at least one of the following:
A) the molecule has a structure selected from the group consisting of: (i) Ax-C, (ii) Ax-C-Ax, (iii) C-Ax-C,
(iv) (C)Z-B-AX-B-(C)Z, (v) (Ax)y-B-C-B-(Ax)y, and mixtures thereof;
B) on any given A moiety there is more than one residue selected from the group consisting of phosphates, phosphonates, phosphinates, or hypophosphites; or salts thereof; C) the molecule has a structure of (Ax)y-B-(C)2 with the proviso that the B moiety and the A moiety are not bound to each other through an alkylidene amine linkage; D) the C moiety is selected from the group consisting of poly(oxyalkylene amine), poly(oxyalkylene diamine), monoalkoxy poly(oxyalkylene amine), monoaryloxy poly(oxyalkylene amine), poly (vinyl pyrrolidones), poly (methyl vinyl ethers), poly(ethylene imines), poly (aery lamides), polyoxazoles, and mixtures thereof; wherein x is an integer from 1 to 3 and represents the number of independent A moieties, y is an integer from 1 to 3 and represents the number of independent chains of A moieties, and z is an integer from 1 to 3 and represents the number of independent C moieties.
The present invention further provides a method of dispersing a cementitious formulation comprising a hydraulic cement in water, comprising providing in said cementitious formulation a dispersant as hereinabove described and mixing said cementitious formulation.
DETAILED DESCRIPTION OF THE INVENTION
The oligomeric cement dispersant of the present invention does not have a polymeric backbone with pendant groups as do dispersants of the prior art. Rather, the oligomeric cement dispersant has a moiety that will adsorb on to the particle to be
dispersed by means of one or more residues attached to an adsorbing moiety of absolute molecular weight. The adsorbing moiety acts as an "anchor" to hold the dispersant on to the particle to be dispersed.
One embodiment of the present invention is a composition of matter adapted for dispersing cementitious particles in water, comprising a reaction product of component A, optionally component B, and component C.
Each component A is independently a nonpolymeric, functional moiety that adsorbs on to a particle, and contains at least one residue derived from a component selected from the group consisting of phosphates, phosphonates, phosphinates, hypophosphites, sulfates, sulfonates, sulfmates, alkyl trialkoxy silanes, alkyl triacyloxy silanes, alkyl triaryloxy silanes, borates, boronates, boroxines, phosphoramides, amines, amides, quaternary ammonium groups, carboxylic acids, carboxylic acid esters, alcohols, carbohydrates, derivatives of carbohydrates, salts of any of the preceding moieties, and mixtures thereof. Derivatives of carbohydrates include, but are not limited to, phosphate esters of sugars, borate esters of sugars, and sulfate esters of sugars.
The salt of moiety A is selected from the group consisting of lithium, sodium, potassium, calcium, magnesium, aluminum, iron, ammonia, amines, and mixtures thereof. The term amines is meant to include primary, secondary, and tertiary amines, including, but not limited to, substituted amines such as triethanolamine or morpholine.
Molecules satisfying the requirement of the A moiety include, but are not limited to, multihydroxy compounds, such as sugars, sugar acids, lactones of sugar acids, sugar alcohols, tris(hydroxymethyl) aminomethane, phosphate esters of sugars, borate esters of sugars, sulfate esters of sugars, alkyl phosphates, substituted alkyl phosphates, alkyl phosphonates, substituted alkyl phosphonates, alkyl phosphinates, substituted alkyl phosphinates, aryl boronic acids, esters of aryl boronic acids, aryl dioxaborolanes, triaryl boroxines, trialkoxyboroxines, alkyl trialkoxy silanes, alkyl triacyloxy silanes, alkyl triaryloxy silanes, hydroxy carboxylic acids, non-polymeric
poly carboxylic acids, and mixtures thereof. The alkyl groups in the above molecules are generally C, to C6 groups, the aryl groups in the above molecules are generally C6 to C10 groups, and the acyl groups in the above molecules are generally C, to C6 groups. The substituted alkyls can be hydroxyalkyls or carboxyalkyls.
Illustrative examples of molecules used to construct the A moiety include, but are not limited to, 2-carboxyethyl phosphonic acid, sulfosuccinic acid, citric acid, 2- phosphono-l,2,4-butane tricarboxylic acid, glucuronic acid, ethylenediaminetetraacetic acid, gluconic acid, cyclohexane hexacarboxylic acid, mellitic acid, saccharic acid, mucic acid, diethylenetriamine pentaacetic acid, glucoheptonic acid, glucoheptonic lactone, lactobionic acid, 3,3' ,4,4'-benzophenone tetracarboxylic acid, 2- (4'carboxyphenyl)-l,3,2-dioxaborolane, triphenyl boroxine, 4-carboxyphenyl boronic acid, 4-formylphenyl boronic acid, 2-(4'-formylphenyl)-l,3,2-dioxaborolane, amino propyl trimethoxysilane, aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxy silane, 3-glycidoxypropyltriethoxysilane, 3-(triethoxysilyl)propyl isocyanate, 3- (trimethoxysilyl)propyl isocyanate, glucooctanoic-γ-lactone, glucose, leucrose, diaminopropane-N,N,N' ,N' -tetraacetic acid, aconitic acid, isocitric acid, 1,2,3,4- butanetetracarboxylic acid, nitrilotriacetic acid, tricarballylic acid, N- (phosphonomethyl)iminodiacetic acid, 3-[[tris(hydroxymethyl)methyl] amino]-l- propanesulfonic acid, 2-[[tris(hydroxymethyl)methyl] amino] -1-ethanesulfonic acid, 3- [bis(2-hydroxyethyl)amino]-2-hydroxy-l-propanesulfonic acid, 3-[N- tr ishydroxymethylmethy lamino] -2-hydroxypropanesulfonic acid, N- tris[hydroxymethyl]methyl-4-aminobutanesulfonic acid, 3-aminoadipic acid, aspartic acid, α-glutamic acid, β-glutamic acid, l,3-diamino-2-hydroxypropane-N,N,N' ,N'- tetraacetic acid, triethylenetetraaminehexaacetic acid, glucosamine, galactosamine, mannosamine, tris(hydroxymethyl)aminomethane, γ-carboxyglutamic acid, glucamine, glucosaminic acid, β-carboxy aspartic acid, α-hydroxymethylaspartic acid, tricine, 1,2,3,4-cyclopentanetetracarboxylic acid, 6-phosphogluconic acid, sorbitol, mannose, mannitol, mannonic acid, mannuronic acid, galactose, galactitol, galactaric acid, galacturonic acid, fructose, sucrose, salts of any of the preceding moieties, and mixtures thereof.
Each A moiety has one or more functional groups. When the A moiety has one functional group, two or more A moieties are combined to provide for multiple functional groups in the oligomeric dispersant. When the A moiety has multiple functionalities, there is no requirement that more than one A moiety must be used. Examples of the residue include, but are not limited to, hydroxyl, carboxylate, sulfate, sulfonate, sulfinate, phosphate, phosphonate, phosphinates, borate, boronate, boroxine, dioxaborolane, amine, quaternary ammonium, and mixtures thereof. The functional groups attach to the cement particle to be dispersed by adsorbing on to the cement particle. The more functional groups that are present on the A moiety, the more strongly the A moiety can anchor to the cement particle.
Component B is an optional moiety, and if present, each B is independently a nonpolymeric moiety that is disposed between the A moiety and the C moiety, and is derived from a second component selected from the group consisting of C] to C6 linear saturated hydrocarbons, C, to C6 linear unsaturated hydrocarbons, Cj to C6 branched saturated hydrocarbons, to C6 branched unsaturated hydrocarbons, C6 to C10 arylenes, nitrogen-containing compounds, and mixtures thereof. Nitrogen-containing compounds include, but are not limited to, any amine.
Illustrative examples of the B moiety include, but are not limited to, methylene, ethylene, n-propylene, n-butylene, n-pentylene, n-hexylene, isobutylene, neopentylene, propenylene, isobutenylene, diethylene triamine, triethylene tetramine, tetraethylene pentamine, or pentaethylene hexamine, phenylene, substituted arylenes such as
Each C component is at least one moiety that is a linear or branched water- soluble nonionic polymer substantially non-adsorbing to cement particles, and is preferably selected from the group consisting of poly(oxyalkylene glycol), poly (oxy alky lene amine), poly(oxyalkylene diamine), monoalkoxy poly(oxyalkylene amine), monoaryloxy poly(oxyalkylene amine), monoalkoxy poly(oxyalkylene glycol),
monoaryloxy poly(oxyalkylene glycol), poly (vinyl pyrrolidones), poly (methyl vinyl ethers), poly (ethylene imines), poly(acry lamides), polyoxazoles, and mixtures thereof.
The C moiety has a number-average molecular weight from 500 to 100,000. Preferably, the C moiety has a number-average molecular weight from 1,000 to 50,000. Most preferably, the C moiety has a number-average molecular weight from 1,000 to 30,000.
The oligomeric dispersant of the present invention has number-average molecular weight from 650 to 100,000. Preferably, the dispersant has a number- average molecular weight from 1,150 to 50,000. Most preferably, the dispersant has a number-average molecular weight from 1,150 to 30,000.
For further clarification, Ax is preferably at least one of A-, A-A-, or A-A-A-;
B-(C)
Z is preferably at least one of
; and
(Ax)y-B is preferably at least one of
In another embodiment, the abovementioned composition of matter is incorporated into a cementitious formulation with a hydraulic cement. The oligomeric dispersant can be added as an admixture alone or in combination with other admixtures in the field, or it can be added to the cementitious formulation prior to delivery to the field.
The hydraulic cement comprising the cementitious formulation for which the dispersants are effective is selected from the group consisting of portland cement,
masonry cement, alumina cement, refractory cement, magnesia cement, calcium sulfoaluminate cement, and mixtures thereof.
Aggregate can be included in the cementitious formulation to provide for mortars which include fine aggregate, and concretes which also include coarse aggregate. The fine aggregate are materials that pass through a Number 4 sieve (ASTM C125 and ASTM C33), such as silica sand. The coarse aggregate are materials that are retained on a Number 4 sieve (ASTM C125 and ASTM C33), such as silica, quartz, crushed round marble, glass spheres, granite, limestone, calcite, feldspar, alluvial sands, or any other durable aggregate, and mixtures thereof.
Additionally, cement admixtures may be included in the cementitious formulation. Admixtures that can be added include, but are not limited to, set accelerators, set retarders, air-entraining agents, air-detraining agents, foaming agents, defoaming agents, corrosion inhibitors, shrinkage-reducing agents, other known dispersing agents, pozzolans, pigments, and mixtures thereof.
The cementitious formulation may further comprise water. The water can be present in an amount from 20% to 100% based on the dry weight of the cement.
The dispersant of the present invention is generally present in the cementitious formulation in an amount from 0.005 to 2% based on the dry weight of the cement. Preferably, the dispersant is present in an amount from 0.01 % to 1 % .
An additive selected from the group consisting of soil, calcined clay, and mixtures thereof can be included in the cementitious formulation. The soil can be any soil including, but not limited to, fine sands, silty soils, and clay. The additive can replace up to 25% of the cement. Preferably, the additive replaces up to 20% of the cement.
In another embodiment of the present invention, there is provided a method of dispersing a cementitious formulation comprising a hydraulic cement in water,
including providing in said cementitious formulation the above-described oligomeric cement dispersant.
In another embodiment of the invention, an oligomeric dispersant wherein at least one A moiety in the oligomeric dispersant is blocked is used in combination with a second dispersant which is selected from another oligomeric dispersant of the present invention or any other suitable cementitious dispersant. By "blocked" it is meant that the residue on the A moiety does not interact with the cement until the residue is liberated. The residue is liberated/deblocked over time by hydrolyzing in the alkaline environment of the cementitious system. This provides for latent dispersant properties.
The effect of liberating over time results in a delay of dispersing performance that leads to extended slump retention performance. The residues on the A moiety that are blocked include, but are not limited to, trialkoxy silanes, triacyloxy silanes, and triaryloxy silanes. A preferred blocked residue is trialkoxy silanes.
The blocked oligomeric dispersant can be present in a cementitious formulation in an amount from 0.005 to 2% based on the dry weight of the cement. Preferably, the blocked oligomeric dispersant is present in an amount from 0.01 % to 1 % . Preferably, the ratio of the blocked oligomeric dispersant to the other dispersant is from 1 : 10 to
5:1. More preferably , the ratio is 1 : 5 to 3 : 1.
By any cementitious dispersant it is meant to include all chemicals that function as a dispersant, water-reducing agent, or plasticizer for cement. Illustrative examples include, but are not limited to, beta-naphthalene sulfonates, lignosulfonates, polyacrylic acids, polymethacrylic acids, polycarboxylates, and polyaspartates.
SPECIFIC EMBODIMENTS OF THE INVENTION
Oligomeric dispersants according to the present invention were synthesized and tested as described below. The molecular weights used herein are number-average molecular weights. The following tests were used: Slump (ASTM C143), Air content
(ASTM C231), and Set time (ASTM C403). Aggregates met the specifications of ASTM C33.
SYNTHESIS EXAMPLE 1 l. lg (0.003 mole) of 1,2,3,4,5,6-cyclohexane hexacarboxylic acid was suspended in 5.5g of deionized water. 6.52g of methoxy polyoxyalkylene amine (JEFFAMINE® M-2070 (XTJ-508) from Huntsman Corporation with a 2000 molecular weight) was slowly added to the mixture to achieve a homogeneous solution. O.OOlg of 4-methoxy phenol was added while stirring the solution. The solution was heated to 180°C under nitrogen gas stream for 60 minutes. The reaction mixture was cooled to room temperature. The reaction product was dissolved in aqueous sodium hydroxide solution to obtain a 39.1 % solids solution at a pH 8.4.
SYNTHESIS EXAMPLE 2 0.57g (3.7 mmole) of 2-carboxyethylphosphonic acid was dissolved in 6g of water and l l. llg (3.7 mmole) of methoxypolyoxyalkylene amine (M3000 from BASF with a 3000 molecular weight) was added. The mixture was heated under nitrogen at 160°C for 4.5 hours.
SYNTHESIS EXAMPLE 3
2.44g of gluconic acid solution (48.2% aqueous solution) was combined with 2g of deionized water in a 50ml round bottom flask. 6.12g of methoxy polyoxyalkylene amine (IEFFAMINE® M-1000 (XTJ-506) from Huntsman Corporation with a 1000 molecular weight) was added in portions while stirring. 0.002g of 4-methoxy phenol was added. The solution was heated to 160°C under nitrogen stream for 90 minutes. The mixture was cooled to room temperature. The reaction mixture was dissolved in water to obtain a 40% solids solution at neutral pH.
SYNTHESIS EXAMPLE 4 A solution of 4.03g (16.3 mmol) of 3-(triethoxysilyl)propyl isocyanate in 20ml of tetrahydrofuran (THF) was added to 0.84g (8.15mmol) of diethylenetriamine in a flask cooled in an ice bath. The mixture was stirred at 0°C for 1 hour, then at ambient
temperature for 4 hours. The solvent was evaporated and the viscous, colorless product was dried in a vacuum.
0.848g (1.42 mmol) of the product was dissolved in 30ml THF. 2.92g (1.42 mmol) methoxy polyoxyethylene glycol-chloroformate, prepared from methoxy polyoxyethylene glycol (MPEG 2000 from Harcros Organics, Inc. with a 2000 molecular weight) and triphosgene, and 0.2ml triethylamine were added to the solution. The mixture was stirred at ambient temperature for 3 hours. The material was filtered and the solvent was evaporated. The resulting pale yellow solid was vacuum dried.
SYNTHESIS EXAMPLE 5
131.6g (0.048 equivalents of amine) of methoxy polyoxyalkylene amine
(JEFFAMINE® XTJ-234 from Huntsman Corporation with a 3000 molecular weight) was combined with lOg (0.048 mole) of α-D-glucoheptonic-γ-lactone in an oven dried 250ml round bottom flask. The stirred mixture was heated to 110°C under a dry nitrogen gas purge for 5.5 hours.
EXAMPLE 1
Dispersants of the present invention were prepared and compared to dispersants of the prior art. For the A moiety, 1,2,3,4,5,6-cyclohexane hexacarboxylic acid was used in all samples for this example. For the C moiety, methoxy polyoxyalkylene amines were used. The following materials were used for the samples: Sample A, JEFFAMINE® M-1000 (XTJ-506) from Huntsman Corporation with a 1000 molecular weight; Sample B, JEFFAMINE® M-2070 (XTJ-508) from Huntsman Corporation with a 2000 molecular weight; Sample C, JEFFAMINE® XTJ-234 from Huntsman Corporation with a 3000 molecular weight; and sample D methoxy polyoxyethylene amine from Shearwater Polymers, Inc. with a 5000 molecular weight. Finally, a beta- naphthalene sulfonate-formaldehyde condensate (BNS) was tested as a comparison. The specific level of dispersant used is listed below in Table 1.
The water to cement ratio used was 0.35. The dispersant and water were hand mixed into 500g of Portland Type I cement and mixed to a uniform consistency. The
paste was then mechanically mixed at 700 rpm for one minute. The results of the testing are shown below in Table 1.
TABLE 1
The molecular weight of the "C" moiety of the oligomeric dispersants of the present invention did not influence the paste mass flow rate and the paste spread diameter. Compared to the BNS dispersants of the prior art, performance was improved.
EXAMPLE 2
The relationship between the number of attached C moieties on the A moiety and performance was tested. For the A moiety, 1,2,3,4,5,6-cyclohexane hexacarboxylic acid was used in all samples for this example. For the C moiety, a methoxy polyoxyalkylene amine, JEFFAMINE® M-1000 (XTJ-506) from Huntsman Corporation with a 1000 molecular weight was used. The molar ratio of the A moiety to the C moiety for the samples were: Sample A 1: 1 (corresponding to general formula i, Ax-C; same sample from Example 1); Sample E 1: 1.25, and Sample F 1 : 1.75 (E and F correspond to general formula iii, C-Ax-C). The prior art comparative example was the same as in Example 1. The samples were prepared as described above in Example 1. The results of the testing are shown below in Table 2.
TABLE 2
As shown in Table 2, as more C moieties are attached to the A moiety, the effectiveness as a dispersant decreases. As more C moieties are added, there are fewer functional groups with which to adsorb on to the particle to be dispersed. Anchor group binding strength is preferably balanced with the C moiety size and number for optimum performance.
EXAMPLE 3
The relationship of A moiety structure on dispersibility was tested at a higher water to cement ratio. Samples A, B, C, D, and F were prepared as described above. Sample G was prepared with 2-carboxyethylphosphonate as the A moiety with a methoxy polyoxyalkylene amine, JEFFAMINE® M-1000 (XTJ-506) from Huntsman Corporation with a 1000 molecular weight, as the C moiety. Also, the samples were compared to a plain paste without any dispersant, and a calcium lignosulfonate dispersant-containing sample was tested as a comparison. The water to cement ratio in this example was 0.42. The mix procedure was the same as in Example 1, except that each paste, except sample G, was stored for five minutes and then mechanically re- mixed for one minute at 700rpm. Sample G was mixed as in Example 1. The test results are shown in Table 3 below.
TABLE 3
The results in Table 3 show that the plain sample and the lignosulfonate sample lose about half of the flow in about 20 minutes. The BNS loses more than half of the initial flow. The dispersants of the present invention, however, lose less than half of the initial flow in the same time period. The dispersants of the present invention perform better than lignosulfonates at a lower dosage, perform better than BNS at the same dosage.
EXAMPLE 4
The relationship of dispersant structure, as influenced by C moiety molecular weight, to initial set time of a cement paste was tested. The dispersants tested were those from the previous examples. The water to cement ratio was 0.35. All dispersants were added at 0.2% based on the weight of cement. The mixing was the same as described above in Example 1. The initial set time was tested using a Form + Test automated set time apparatus using 300g of each prepared paste. The results are listed in Table 4 below.
TABLE 4
N/A = not applicable
Table 4 shows that as the molecular weight of the C moiety increases, the initial set time is reduced.
EXAMPLE 4A
The relationship of the number of attached C moieties on the A moiety in the dispersant structure to initial set time of a cement paste was tested. The dispersants are those from the previous examples. The water to cement ratio was 0.35. All dispersants were added at 0.2% based on the weight of cement. The mixing was the same as above Example 1. The initial set time was tested using a Form + Test automated set time apparatus using 300g of each prepared paste. The results are listed in Table 4 A below.
TABLE 4A
N/A = not applicable
The results in Table 4A show that as more C moieties are attached to the A moiety, the initial set time decreases.
EXAMPLE 5
The relationship of the A moiety functionality to fluidity of a cement paste was tested. The water to cement ratio was 0.35. The preparation of the paste samples was the same as in Example 3 above. The C moieties for the samples were methoxy polyoxyalkylene amine, JEFFAMINE® M-1000 (XTJ-506) from Huntsman Corporation with a 1000 molecular weight, for Samples 2-6, and methoxy polyoxyethylene glycol from Union Carbide Corporation with a 2000 molecular weight, for Sample 1.
TABLE 5
The total number of active functional groups on the A moiety(s) influences the performance of the dispersant. As the total number of active functional groups increases, the dispersing performance increases.
EXAMPLE 6
The A moiety was varied to compare performance against prior art dispersants and a plain cement paste reference. The A moieties tested are listed below in Table 6.
The C moiety was a methoxy polyoxyalkylene amine, JEFFAMINE® XTJ-234 from
Huntsman Corporation with a 3000 molecular weight. The reference dispersant was a polymeric carboxylate backbone with polyether group side chains. The water to cement ratio was 0.35. The mix procedure was the same as in Example 1. The results are listed below in Table 6.
TABLE 6
The results in Table 6 show improved dispersant performance by the oligomeric dispersants over the calcium lignosulfonate and BNS dispersants, and comparable performance to the polymeric carboxy late/poly ether dispersant. Also, glucoheptonate
(with 6 hydroxyl groups) as the A moiety performs better than gluconate (with 5 hydroxyl groups) as the A moiety.
EXAMPLE 7
Several dispersants according to the present invention were compared to a plain sample and a calcium lignosulfonate dispersant in a concrete formulation. The A moiety was either gluconate or glucoheptonate. The C moiety was a methoxy polyoxyalkylene amine, being either JEFFAMINE® M-2070 (XTJ-508) from Huntsman Corporation with a 2000 molecular weight or JEFFAMINE® XTJ-234 from Huntsman Corporation with a 3000 molecular weight.
The plain mix consisted of 12.1kg of Portland cement, 37.8kg of crushed stone,
24.9kg of sand, and 6.65kg of water to provide a water to cement ratio of 0.55. The amount of dispersant is listed below in Table 7. The mixes were adjusted with sand and stone to compensate for the reduced water requirement with a dispersant to
maintain a constant concrete volume for all mixes. Dispersed mixes contained less water, as indicated by the % water reduction in Table 7.
The concrete mixer was loaded with a portion of the mix water. The dispersant, stone, cement and sand were added to the mixer. The mixer was started and the remaining water was added. The mixture was mixed for 5 minutes at a drum rotation rate of about 19 rpm. Note, mixes 3-6 contained a defoamer, which was a non-silicone proprietary mixture sold as SURFYNOL® DF-75 from Air Products, added at 0.75% by weight of the dispersant.
TABLE 7
Oligomeric dispersant produces greater water reduction than lignosulfonate dispersants at the same dosage. Better performing oligomeric dispersants were less retarding with greater water reduction and produced higher concrete compressive strength. Glucoheptonate anchor performs better than the gluconate anchor.
EXAMPLE 8
A concrete batch was prepared to compare dispersants of the present invention to BNS and polycarboxylate dispersants. The dispersant of the present invention used a glucoheptonate molecule as the A moiety and as the C moiety, a methoxy polyoxyalkylene amine, namely JEFFAMINE® M-2070 (XTJ-508) from Huntsman Corporation with a 2000 molecular weight (2K), or JEFFAMINE® XTJ-234 from Huntsman Corporation with a 3000 molecular weight (3K). The reference dispersant was a polymeric carboxylate backbone with polyether group side chains.
The mix consisted of 20.5kg of Portland cement, 61kg of crushed stone, 46kg of sand, and 9.03kg of water to provide a water to cement ratio of 0.46. The amount of dispersant is listed below in Table 8.
The concrete mixer was loaded with a portion of the mix water. The dispersant, stone, cement and sand were added to the mixer. The mixer was started and the remaining water was added. The mixture was mixed for 5 minutes at a drum rotation rate of about 19 rpm. The slump and air were measured initially. The mixer rate was reduced to about 4 rpm until one minute before each sample time. At one minute before taking the sample, the mixer rate was increased to about 19 rpm. Note, all mixes, except the BNS mix, contained a defoamer, which was a non-silicone proprietary mixture sold as SURFYNOL® DF-75 from Air Products, added at 0.75% by weight of the dispersant.
TABLE 8
The results in Table 8 show that the dispersant of the present invention has improved slump retention as compared to BNS, and performs comparably to the reference polycarboxylates to provide improved slump retention properties.
EXAMPLE 9
The alkoxysilane dispersant that was prepared as in Synthesis Example 4 was tested in combination with a polycarboxylate dispersant in a cementitious mixture. The polycarboxylate dispersant was a polymeric carboxylate backbone with polyether group side chains. The cementitious formulation was prepared as described in Example 8. Both samples contained a defoamer, which was a non-silicone proprietary mixture sold as SURFYNOL® DF-75 from Air Products, added at 0.75% by weight of the dispersant. The results are reported in Table 9.
TABLE 9
The alkoxysilane dispersant improved concrete slump retention without increasing set time and decreasing early age concrete compressive strength.
EXAMPLE 10
The alkoxysilane dispersant that was prepared as in Synthesis Example 4 was tested in combination with another oligomeric dispersant in a cementitious paste. The cementitious paste was prepared as described in Example 1 with a water to cement ratio of 0.35. The other oligomeric dispersant had glucoheptonate as the A moiety and JEFFAMINE® M-2070 (XTJ-508) from Huntsman Corporation with a 2000 molecular weight as the C moiety (Other). The alkoxysilane "blocked" or latent dispersant was added at the dosages described below in Table 10.
TABLE 10
The results in Table 10 show that the alkoxysilane dispersant significantly increases the duration of the dispersed state when used in combination with another oligomeric dispersant. The effect of the alkoxysilane dispersant is related to dose, and it increases with increasing dose.
The present invention therefore is demonstrated to provide an oligomeric dispersant for dispersing cementitious particles, wherein the dispersant adsorbs on to the particle to be dispersed to provide a material that is several times more efficient than traditional dispersants, such as beta naphthalene sulfonates, sulfonated melamine formaldehyde condensates, or calcium lignosulfonates, and to provide a full range (Type A to Type F) water reducing capability.
The present invention also includes the novel oligomeric dispersants which includes a molecule which is reaction product of component A, optionally component B, and component C; wherein each component A is independently a nonpolymeric, functional moiety that adsorbs on to a cementitious particle, and contains at least one residue derived from a first component selected from the group consisting of phosphates, phosphonates, phosphinates, hypophosphites, sulfates, sulfonates, sulfinates, alkyl trialkoxy silanes, alkyl triacyloxy silanes, alkyl triaryloxy silanes, borates, boronates, boroxines, phosphoramides, amines, amides, quaternary ammonium groups, carboxylic acids, carboxylic acid esters, alcohols, carbohydrates, phosphate esters of sugars, borate esters of sugars, sulfate esters of sugars, salts of any of the preceding moieties, and mixtures thereof; wherein component B is an optional moiety, where if present, each component B is independently a nonpolymeric moiety that is disposed between the component A moiety and the component C moiety, and is derived from a second component selected from the group consisting of linear saturated hydrocarbons, linear unsaturated hydrocarbons, saturated branched hydrocarbons, unsaturated branched hydrocarbons, alicyclic hydrocarbons, aryl, phosphoester, nitrogen containing compounds, and mixtures thereof; and wherein component C is at least one moiety that is a linear or branched water soluble, nonionic polymer substantially non-adsorbing to cement particles, and is selected from the group consisting of poly(oxyalkylene glycol), poly(oxyalkylene amine), poly(oxyalkylene diamine), monoalkoxy poly(oxyalkylene amine), monoaryloxy poly(oxyalkylene amine), monoalkoxy
poly(oxyalkylene glycol), monoaryloxy poly(oxyalkylene glycol), poly (vinyl pyrrolidones), poly (methyl vinyl ethers), poly (ethylene imines), poly (aery lamides), polyoxazoles, and mixtures thereof; wherein if the A moiety contains any phosphate, phosphonate, phosphinate, or hypophosphite residue the molecule is further characterized by at least one of the following:
A) the molecule has a structure selected from the group consisting of: (i) Ax-C, (ii) Ax-C-Ax, (iii) C-Ax-C,
(iv) (C)Z-B-AX-B-(C)Z, (v) (Ax)y-B-C-B-(Ax)y, and mixtures thereof; B) on any given A moiety there is more than one residue selected from the group consisting of phosphates, phosphonates, phosphinates, or hypophosphites; or salts thereof;
C) the molecule has a structure of (Ax)y-B-(C)Z with the proviso that the B moiety and the A moiety are not bound to each other through an alkylene amine linkage;
D) the C moiety is selected from the group consisting of poly(oxyalkylene amine), poly(oxyalkylene diamine), monoalkoxy poly(oxyalkylene amine), monoaryloxy poly(oxyalkylene amine), poly (vinyl pyrrolidones), poly (methyl vinyl ethers), poly (ethylene imines), poly(acry lamides), polyoxazoles, and mixtures thereof; wherein x is an integer from 1 to 3 and represents the number of independent A moieties, y is an integer from 1 to 3 and represents the number of independent chains of A moieties, and z is an integer from 1 to 3 and represents the number of independent C moieties; as more fully described above.
Preferably the molecule has a structure selected from the group consisting of (i) Ax-C; (ii) Ax-C-Ax; (iii) C-Ax-C;
(iv) (Ax)y-B-(C)Z; (v) (C)Z-B-AX-B-(C)Z; (vi) (Ax)y-B-C-B-(Ax)y; and mixtures thereof, wherein x is an integer from 1 to 3 and represents the number of independent A moieties, y is an integer from 1 to 3 and represents the number of A
moieties, and z is an integer from 1 to 3 and represents the number of independent C moieties.
Preferably, the molecule is represented by one of the following structures:
wherein R is at least one of H, CrClg (preferably CrC6) alkyl, phenyl, benzyl, or alkyl sulfonate each R is independently at least one of H, methyl, ethyl, propyl, or styrene
Q is at least one of carboxylic ester or amide G is at least one of -OH, -COOH, a phosphate, a phosphonate, a phosphinate, a hypophosphite n = 10-500 m = 5-7
wherein R
2 is at least one of H, C,-C
18 (preferably C,-C
6) alkyl, phenyl, benzyl, or alkyl sulfonate each R is independently at least one of H, methyl, ethyl, propyl, or styrene n = 10-500
wherein Rλ is at least one of H, CrC18 (preferably CrC6) alkyl, phenyl, benzyl, or alkyl sulfonate each R is independently at least one of H, methyl, ethyl, propyl, or styrene
n = 10-500
wherein Rλ is at least one of H, CrClg (preferably CrC6) alkyl, phenyl, benzyl, or alkyl sulfonate each R is independently at least one of H, methyl, ethyl, propyl, or styrene n = 10-500
wherein Rj is at least one of H, CrC18 (preferably CrC6) alkyl, phenyl, benzyl, or alkyl sulfonate each R is independently at least one of H, methyl, ethyl, propyl, or styrene
each X is independently at least one of urea, carboxylic ester, or amide
R2 is Cj to C6 alkyl n = 10-500;
and
wherein Rt is at least one of H, CrC18 (preferably CrC6) alkyl, phenyl, benzyl, or alkyl sulfonate each R is independently at least one of H, methyl, ethyl, propyl, or styrene R2 is Cj to C6 alkyl n = 10-500
Naturally, more than one of such molecules may be used.
It should be appreciated that the present invention is not limited to the specific embodiments described above, but includes variations, modifications and equivalent embodiments defined by the following claims.