CA1238437A - Superplasticizer composition - Google Patents

Abstract

ABSTRACT

An improved superplasticizer composition is produced by substi-tuting whey, which is a by-product of the manufacture of cheese from milk, for a portion of known superplasticizers such as alkali salts of sulfonated polymers and oligomers. The resulting super-plasticizer composition, which is cheaper than conventional super-plasticizers, imparts extended slump retention to concrete and other mineral slurries.

Description

The present invention relates to a super plasticizer useful for imparting fluidization to, and improving the slump of mineral slurries such as concrete and other mortar mixes, and more particularly to such a super plasticizer modified with whey or with the constituents of whey. Such super plasticizers are generally alkali salts of sulfonated polymers and oligomers and may include sulfor.ated mailmen formaldehyde condensates, alkali salts of lignosulfonates, and alkali salts of naphthalene sealants The products of the present invention may be prepared in the form of aqueous solutions or spray dried powders, and are intended to impart prolonged fluidization of cement products and other mineral slurries.

Super plasticizers have long been known and used to improve the physical properties and handling abilities of various mineral slurries and muds, such as cementitious slurries, grouts, mortars and drilling muds. Such super plasticizers may be used to improve the fluidity, increase the fluid retention and lengthen the active life of such products.

For example, it is well known that higher compressive strengths in concrete are obtained by using a relatively low water-cement ratio, but a concrete mix having a water-cement ratio sufficiently low to obtain maximum desired compressive strength is more difficult to handle and place than a similar concrete mix having higher water-cement ratios. The use of a super plasticizer in a concrete mix allows the water content of the mix to be kept to a level that will yield a satisfactorily high compressive strength, but still reduces the slump of the mix to facilitate placing of the mix for example, by pumping.

Particularly useful superplasticiæers are those of the anionic amino resin type, in which, for example the anionic character may be provided by sulfonic groups. The amino resin component may be a condensation product of mailmen and formaldehyde and may be an admixture with urea and/or dicyandiamide~

Sulfona~ed mailmen formaldehyde condensates which in this disco-sure include those in which the melamlne is replaced partially by urea and/or dicyandia~ide, are known to impart fluidization to concrete and mortar mixes. See, for example, U.S. Patent Nos.

2,730,516, 3,121,702, 3,240,736, 3,941,734 and 3,9~5,6~6, and U.S. Patent No. 893,901. However all of these super plasticizers demonstrate a limited active life for sustaining the fluidity of the mineral slurries, namely concrete, mortar, ceramic and gypsum aqueous mixes in which they are intended to be used. Furthermore, several of these super plasticizers are known to cause "bleeding", or separation of the fluid and solid constituents of for example, a cementitious slurry.

It has now been found that the action of these super plasticizers may be improved by incorporating whey, or the constituents of whey, into the super plasticizer. The resulting super plasticizing combo-session increases the active life of, and gives greater fluid retention to, mineral slurries such as concrete and mortar mixes than heretofore known super plasticizers. Furthermore, as whey is substantially cheaper than the aforementioned super plasticizers, the substitution ox whey for a portion of those results in a less expensive super plasticizing composition.

The whey which is contemplated for use in the compositions of the present invention is a by-product of the production of cheese from milk; whey and its constituents constitute about 85 to 90% by volume of the amount of milk used in the cheese-making process. In other words, only about 10 to 15% by volume of the mill is used;
the rest, mainly whey, is left to be used or disposed of.
Consequently, large quantities of whey are readily available as a by-product or waste product of the production of cheese at a relatively low cost.

Although substantial quantities of whey powder are used in ice cream and various confectionery preparations, substantial amounts - remain to be disposed of as waste.

As produced, whey is a relatively dilute solution of lactose and proteins; typical compositions of various whey products are shown in the following table:

Component Sweet Whey Acid Whey Salt Whey Whey Permeate .

Total Solids 6.4% 6.5~ 10.7~ 6.1 water 93.7 93.5 89.2 94.2 Lactose 4.9 4.9 4-4 4-9 % Protein I 0.8 0.7 0.1 % Nail 0.0 0.0 4.7 0.0 10 % Ash 0.5 0.8 5.3 0.7 Lactic Acid 0.05 0.4 0.0 0.4 pi 5.9-6.34.4-4.6 5.0-5.4 4.5-508 In this specification and in the claims appended hereto, the term "whey" is used to refer both to the liquid by-product of the cheese making process, whether in its original state or concentrated or diluted, and to whey solids containing the essential constituents of whey.

As noted above, a substantial portion of the whey produced in the manufacture of cheese is not being used and presents a serious disposal problem as it has a high biological oxygen demand (BUD) of about 60,000 my. The present invention uses whey to produce a water soluble superplasticiziny composition by co-reacting or lending whey products with such super plasticizers as sulfonated mailmen formaldehyde condensates, alkali salts of naphthalene sulfonates and lignosulfonates.

Such super plasticizing compositions in which a portion of super plasticizer is replaced with whey substantially prolong the period of extended slump when used in cementitious slurries, and reduce the "bleeding' problems associated with some of the known and previously used super plasticizers.

Furthermore, the substitution of whey for a portion of the super plasticizer results in a super plasticizing composition of lower cost, as, normally, no increase in the amount of superplasticizin~ composition to be added to the mineral slurry is required to obtain the improved results of the present invention Some of the superplasticiziny compositions of the present invention may be prepared simply by substituting whey for a portion of the super plasticizer either when the super plasticizing composition is prepared or when it is added to the mineral slurry in which it is intended to be used.

In the case of the sulfonated mailmen formaldehyde condensates and other anionic amino resin compositions, -the whey may be incorporated into the composition at a number of stages in the manufacture of the finished product. These stages generally include:

1. An initial alkaline stage during which the pi is maintained between 10 and 12 and the temperature is allowed to rise to about 80C maximum to effect the methylolation and sulfonation of the amino reactants;

2. An acid stage in which the pi is reduced to between about 1.5 and 5.0 and the temperature reduced to between about 40C and ~0C to effect polymerization;

3. A neutralization stage in which the pi is adjusted to between about 7.5 and I at a temperature of about 90C maximum;

4. Blending and adjustment of the composition to specifications.

5. on optional spray drying slave to convert the composition to a fine dry powder.

For example, all of the components, including the whey may be mixed together and then condensation may be effected between the mixed reactants in a single step process to produce an assay solution.

Alternatively, the reactants, such as mailmen, urea, dicyaniamide, formaldehyde and alkali metal salts of sulfurous acid may first be condensed, and then the whey added to produce an aqueous solution which is then neutralized.

As a further alternative, the reactants may be condensed and then neutralized to a finished sulfonated amino resin, which may then be blended or admixed with the whey to produce an aqueous solution.

The aqueous solutions so obtained may be spray dried, if desired, to obtain a fine, dry powder.

In the composition of the present invention, all types of whey, including the aforementioned can he utilized, provided they are chemically compatible with the product in which the super plasticizer is to be used. Certain characteristics of some of the types of whey available would make it obvious to a person skilled in the art that those types could not be used in certain mineral slurries. For example, salt whey would not generally be suitable for use in cement products.

In practice it is preferable, although not necessary, to utilize concentrated whey of about 30% to 50% total solids, which can ye obtained by the evaporation of water from the by-product of cheese production.

Generally the weight ratio of the whey to other active components of the super plasticizing composition will be from about 0.2 to 1.0 to about 2.0 to 1.0; a weight ratio of from about 0.4 to 1.0 to about 0.7 to 1.0 is preferred.

The products of this invention, whether in the aqueous or powder form, can be added to such mineral slurries as concrete, mortar, ceramic, oil muds, gypsum and such like aqueous mixes at levels between 0.3% and 2.5~ based on the weight of the solids in the super plasticizing composition and on the weight of the active ingredient in the aqueous mix, which in the case of concrete is the cement.

3'7 The addition of the superplas~icizing composition of the present invention greatly improves the ability of the mineral slurries to be handled and placed. For example, the addition of this novel super plasticizing composition to concrete increases the slump of concrete mixes, at normal water-cement ratios, to from 70mm Jo 250mm in 10 minutes. The decline in slump back to 70~n will generally take up to about 90 to 110 minutes.

On the other hand, a similar cementitious mixture containing a similar amount of superplasticizincJ composition, but made without whey, would generally hole] a slump greater than 70mm only for about 25 minutes.

Furthermore, the composition of the present invention, when used either in aqueous or powder form and added to concrete mixes containing reduced amounts of water, will maintain workability of such concrete mixes for periods of time Up to 110 minutes. During this extended period the concrete mixes can be poured to produce cured structures of high compressive strengths, up to double the compressive strength of those of regular concrete mixes made with normal water content.

The products of this invention make it possible to obtain high strength concrete with little difficulty as they allow a substantial reduction of water content without loss of workability. They also maintain the surface tension of water and therefore prevent bleeding of the concrete and consequent segregation of its fluid and solid components.

In order that those persons skilled in the art may more fully understand the inventive concept the following examples are set forth for purposes of illustration (In these examples, all viscosity measurements are by the Gardiner-Holt method.) Example I

The following materials were loaded in quick succession into a suitable reaction flask: 520 parts of water, 28 parts of 50% Noah I

solution, 547 parts mailmen, 915 parts of 50% formaldehyde and 520 parts of sodium metabisulfite. The temperature was raised and maintained at 75C and the pi between 11 and 12 for 60 minutes. At the end of -this period 1800 parts of a 30% sweet whey solution was added and the tempera-lure was reduced to 50C. The pi was adjusted at 2.5 to 3.0 with a 20% solution of sulfuric acid and the temperature was held at 45C until a viscosity of C-D was attained.
Then the pi was adjusted to 8.0 with a 50% solution of Noah and -the temperature was raised and held at 90C for 60 minutes. Then -the batch was cooled to 30C and adjusted to 37-38% solids, a viscosity of A-B and a pH=8.0-8.5.
The water tolerance was found to be infinite.
One part of -this material was added to a concrete mix contain-in 184 parts aggregates, 104 parts sand, 64 parts cement NIX and 32 parts water. The initial slump was measured as 250mm which declined to 80mm in 110 minutes. Therefore, the concrete mix had retained its workability 110 minutes after it was prepared. No bleeding or segregation was observed. A control test using a sulfonated amino resin identical to that given in this example but without whey gave an initial slump of 250mm but which declined down to 70mm in 25 minutes.
Example II
A 30% sweet whey solution as used in Example I was fed into a spray drier without further dilution, using the inlet temperature at 200C and an outlet temperature at 90C. A fine particle size powder was produced with a moisture content of 2.0%, which was readily soluble in water.
0~4 parts of this material were added to the concrete mix described in Example I. An initial slump of 230mm was obtained which declined -to 90mm in 110 minutes. A control test using a sulfonated amino resin powder identical to that of Example I but without whey gave an initial slump of 245mm which declined down to 60mm in 25 minutes.

1 ..

Example III

The following materials were loaded in quick succession into a suitable reaction flask: 520 parts of water, 28 parts of 50% Noah solution 547 parts mailmen, 915 parts of 50~ SHEA, and 5~0 parts of sodium metabisulfite. The temperature was raised and maintained at 75C and the pi at 11-12 for 60 minutes. The pi was then adjusted to 3.0~3.5 with a 20~ solution of sulfuric acid and 490 parts of water were added. The temperature was held at 45C until a viscosity E-F was attained. Then 1800 parts of a 30~ whey solution were added and the pi was adjusted to 8.0 with a 50%
Noah. The temperature was raised and held at 90C for 60 minutes.
Then the batch was cooled to 30C and adjusted to 37-38% solids, a viscosity of A-B and a p~--8.0-8.5. The water tolerance was found to be infinite.

The slump retention of this material was found to be 110 minutes from an initial slump of 250mm to 80mm.

Example IV
. _ _ The aqueous solution product of the Example III was spray dried under the same conditions as in Example II. The slump retention of this material I solids on cement was found to he 110 minutes from an initial slump of 260mm to 80mm.

Example V

The following materials were loaded in quick succession into suitable reaction flask: 520 parts of water, I parts of 50% Noel, 440 parts mailmen, 51 parts urea, 915 parts of 50~ SHEA and 520 parts sodium metabisulfite. The temperature was maintained at 75C
and the pi at 11-12 for 60 minutes. Then the pi was adjusted at 3.0-3.5 with a 20~ sulfuric acid and 490 parts water were added The temperature was held at 45C until a viscosity E-F was attained. Then the pi was adjusted at 8.0 with a 50% Noah and the temperature was raised and held at 90C for 60 minutes. As the I. I

batch was cooled 1800 parts of a 30~ whey solution were added.
Finally the batch was adjusted at 37-38~ solids, at viscosity and at p~=8.0-8.5. The water tolerance was found to he infinity The slump retention test gave an initial slump of 270mm which declined to 80mm in 110 minutes.

Example VI

The aqueous solution product of the Example V was spray dried under the same conditions as in Example II. The slump retention test gave an initial slump of 250mm, which declined to 80mm in 110 minutes.

Example VII
. .
The example of example V was prepared except that 70 parts of dicyandiamide were used in place of the 51 parts of urea. The progress of the reaction and the final analysis were identical to those of Example V. The slump retention test gave an initial slump of 250mm, which declined to 80mm in 110 minutes.

Example VIII

The aqueous solution obtained in Example VII was spray dried under the established conditions. The slump retention tusk gave an initial slump of 240mm7 which declined to 70mm in 110 minutes.

Example IX
.

All the products obtained in the previous eight examples were tested in high strength concrete where the water was reduced by 30%
and the level of addition of the materials prepared by those Examples was 1.00~ on cement. The following results were obtained ,.~

~3~3~3'7 Example Slump(mm) Compressive Strength(psi) Initial Mooney omen 1 day _ ye 28 days

6 68 43 25 5200 7100 8500

7 85 55 35 5800 7500 9000

8 65 I 30 5500 7200 8600 Control unheroical - - -no fluidizer Control 70 30 - 3000 ~700 5700 no fluidizer;
no water reduction The above results show that it is extremely difficult to obtain high strength concrete by the reduction of water and still maintain good pump ability unless a fluidizing agent is added. The presence of a fluidizing agent makes it possible to reduce water in concrete and thereby achieve high compressive strengths. Furthermore the fluidizing agent of this invention renders concrete workable for extended periods of time ( 110 minutes).

The fluidizillg properties of the products of this invention can be utilized not only for the flowing and the high strength concrete but also in ceramic and gypsum preparations, as well as in oil well drilling muds.

Example X

300 parts of a 30% solution of sodium lignosulfonate was thoroughly blended with 100 parts of a 30% whey solution and the resulting solution was added to the concrete mixture at a level of 0~4%

, , solids on cement. The slump retention was 110 minutes frown an initial slump of 300mm to a final slump of 8nmm.

Example XI

The aqueous solution product of the Example X was spray dried under the same conditions as in Example II. The slump retention was 110 minutes from an initial slump of 270mm to 80mm.

Example XII
.

The procedure of Example X was repeated using the Sydney salt of naphthalene sulfonate instead of the sodium lignosulfonate used in Example X. Comparable results were obtained.

Example XIII

The procedure of Example XI was repealed using the sodium salt of naphthalene sulfonate instead of the sodium lignosulfonate used in Example XI. Comparable results were obtained.

Claims (15)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A superplasticizing composition comprising whey and one or more alkali salts of sulfonated polymers or oligomers.

2. A superplasticizing composition comprising whey and superplasticizer selected from the group consisting of sulfonated melamine formaldehyde condensates, alkali salts of lignosulfonates and alkali salts of naphthalene sulfonates.

3. A composition according to claim 1 in liquid form.

4. A composition according to claim 1 in dry powder form.

5. A superplasticizing composition according to claims 1, 2 or 3 comprising from about 0.2 to 1.0 parts by weight of whey and from about 2.0 to 1.0 parts by weight of the other active ingredients of the superplasticizing composition.

6. A superplasticizing composition according to claims 1, 2 or 3 comprising from about 0.4 to 1.0 parts by weight of whey and from about 0.7 to 1.0 parts by weight of the other active ingredients of the superplasticizing composi-tion.

7. A mineral slurry admixed with a superplasticizing composition comprising whey and one or more alkali salts of sulfonated polymers or oligomers.

8. A cementitious slurry according to claim 7 comprising from about 0.4 to 1.0 parts by weight of whey and from about 0.7 to 1.0 parts by weight of the other active ingredients of the superplasticizing composition.

9. The cementitious slurry of claim 7 in which the superplasticizing composition is present in amount of from about 0.3 to about 2.5 parts by weight per 100 parts by weight of the cement components of the slurry.

10. A method of improving the workability of cementitious slurries, comprising admixing with the slurries an effective amount of a superplasticizing composition comprising whey and one or more alkali salts of sulfonated polymers or oligomers.

11. A method for extending the period of reduced slump of a cementitious slurry comprising admixing with the slurries an effective amount of a superplasticizing composition comprising whey and one or more alkali salts of sulfonated polymers or oligomers.

12. A dry, cementitious product comprising cement and a superplasticizing composition in powder form, said superplasti-cizing composition comprising whey and a superplasticizer selected from the group consisting of sulfonated melamine formaldehyde condensates, alkali salts of lignosulfonates, and alkali salts.

13. A superplasticizing composition comprising whey and a sulfonated melamine formaldehyde condensate.

14. A superplasticizing composition comprising whey and an alkali salt of a lignosulfonate.

15. A superplasticizing composition comprising whey and an alkali salt of a naphthalene sulfonate.