US 3849327 A
Description (OCR text may contain errors)
iSalvo et a1.
[451 Nov. 19,1974
1 1 MANUFACTURE OF FREE-FLOWING PARTICULATE HEAVY DUTY SYNTHETIC DETERGENT COMPOSITION CONTAINING NONIONIC DETERGENT AND ANTI-REDEPOSITION AGENT  Inventors: Walter A. DiSalvo, North Arlington;
Frank R. Smith, Jr., North Plainfield; Edward ,1. Kenney, Bernardsville, all of NJ.
 Assignee: Colgate-Palmolive Company, New
 Filed: Feb. 9, 1972  Appl. No.: 224,694
Related US Application Data  Continuation-impart of Ser. Nos. 124,1 l 1, March 15, 1971, and Ser, No. 134,324, April 15, 1971, and Ser. No. 203,365, Nov, 30, 19711  US. Cl 252/109, 252/135, 252/531, 252/532, 252/536, 252/538, 252/539, 252/540  Int. Cl. ..Clld 3/065,C1ld 11/02  Field of Search ..252/l35.531.532.535.
 References Cited UNITED STATES PATENTS 3,519,570 7/1970 McCarty 252/135 3,538,004 11/1970 Gabler et a1. .4 252/99 3,562,171 2/1971 Guida 3,630,920 12/1971 Freifeld et a1. 252/90 FOREIGN PATENTS OR APPLICATIONS 511,415 5/1951 Canada 808,945 2/1969 Great Britain 918,499 2/1963 Great Britain 939,878 10/1963 Great Britain 1,212,939 11/1970 Great Britain Primary ExaminerLeon D. Rosdol Assistant E.\'aminerP. E. Willis Attorney, Agent. or FirmSteven J. Baron; Norman Blumenkopf; Herbert S. Sylvester  ABSTRACT 10 Claims, 3 Drawing Figures Pmmm 3,849,327
SHEET 10? 2 PATENTE 112V 1 91974 3,849,327
SHEET 2 or 2 MANUFACTURE OF FREE-FLOWING PARTICULATE HEAVY DUTY SYNTHETIC DETERGENT COMPOSITION CONTAINING NONIONIC DETERGENT AND ANTI-REDEPOSITION AGENT This application is a continuation-in-part of our applications Ser. Nos. 124,1 1 1, filed Mar. 15, 1971; 134,324, filed Apr. 15, 1971; and 203,365, filed Nov. 30, 1971.
This invention relates to a method of making a freeflowing heavy duty built synthetic organic detergent powder containing nonionic synthetic organic detergent and organic anti-redeposition agent. More particularly, it relates to a method of making such a built detergent composition and avoiding product flow problems by mixing a powdered anti-redeposition agent with spray dried intermediate detergent composition particles and spraying onto the surfaces of the mixed particles a liquid nonionic detergent which becomes a solid or semi-solid upon cooling.
Heavy duty synthetic organic detergents for use in automatic washers are known. They are often based on synthetic organic detergent materials, builders and anti-redeposition agents, such as polyvinyl alcohol or so dium carobxymethyl cellulose. In such compositions the cleaning power of the synthetic organic detergent is increased by the presence of the builder. The antiredeposition agent prevents the released soil from being re-desposited on the items washed when the rinse water is removed and drained from the washing machine through such items. Most of the synthetic organic detergents employed in commercial washing compositions have been anionic materials, such as the sulfated and sulfonated detergents containing lipophilic hydrocarbon or similar group and solubilizing salt moieties, but nonionic detergents such as poly-lower alkoxylated compounds have also been employed.
To manufacture detergent compositons containing anionic detergent, synthetic anti-redeposition agent and builder salt the spray drying process has been the most popular, in which an aqueous slurry of the material is atomized at the top of a drying tower and drying air passing into contact with the sprayed droplets evaporates moisture from them as they fall through the tower. This produces a particulate product of atrractive, essentially hollow globular appearance. When nonionic detergents are utilized in the formulation it has been discovered that there are often losses of such products through the tower exhaust and the fumes produced are noticeable and objectionable air pollutants. Also, because the nonionic compounds used have often been liquids, they sometimes created additional drying problems. Accordingly, it has been preferred to utilize solid nonionics, if they are to be employed at all, and to blend them mechanically with other dry detergent constituents to produce a detergent powder. However, such a powder is not as attractive in appearance as spray dried beads and the constituents thereof may sometimes settle during shipment or warehousing. Ad ditionally, such powders are sometimes tacky and poor flowing, often tending to lump or cake in the box, which meets with consumer disapproval and accordingly, is highly objectionable.
In an effort to make attractive and free-flowing detergent compositions containing nonionic detergents or surface active agents, without causing objectionable pluming or waste of nonionic detergent in the spray drying process, the present inventors endeavored to mix nonionic detergent with previously spray dried built synthetic organic detergent compositions. However, even when the nonionics were sprayed onto the rapidly moving surfaces of the detergent composition particles the product resulting was often tacky, lazy and poorly flowing and sometimes tended to cake in storage. Although this effect could be diminished by decreasing the proportion of nonionic detergent uti lized or by employing longer chain length nonionics so that they would harden to almost crystalline. rather than waxy of fatty-like substances, such changes inhibited optimum formulations of the products for best cleaning effects with the various builder salts employed. Ultimately, it was discovered that the synthetic organic soil anti-redeposition agent in the formulation was the cause of the product having poor flow properties. However, elimination of it from the formulation resulted in a product in which the soil was not sufficiently peptized or held in suspension so as to avoid producing wash having redeposited greases and curds in some locations thereon. Surprisingly enough, it was then discovered that if the anti-redeposition agent was post-blended with the spray dried intermediate detergent composition beads, and nonionic detergent or surface active agent was sprayed onto the mixture, while keeping it in motion, the product made could be freeflowing. Of course, it still has the desirable properties of the nonionic detergent utilized and the soilsuspending properties of the anti-redeposition agent.
The products made according to this invention are free flowing and do not segregate or sift in the box on storage. It appears that the nonionic detergents, even if in a normally liquid state (although it is preferred to utilize normally solid or semi-solid detergents), penetrate to the interiors of the hollow spray dried globules and thereby do not leave a film of sticky or adhering material on the surfaces of the detergent beads. Yet, they appear to hold the powdered anti-redeposition agent to the detergent beads or enable such materials also to penetrate into the bead interiors. Of course, some of the nonionic detergent remains on the surfaces of the beads where it contributes an initial wetting effect as soon as the detergent composition is added to wash water.
That the method of the present invention overcomes the problems recited is surprising in view of the fact that the anti-redeposition agent, usually a synthetic organic gum, does not account for a substantial proportion of the spray dried detergent intermediate composi tion. Therefore, it would be expected that surface effects of the beads would be attributable to the builder salts and possibly to the synthetic organic detergent, rather than the very minor anti-redeposition component. Furthermore, it is surprising that by use of the same material and making it even more accessible to the surface of the detergent beads, the poor flow properties of the composition containing nonionic detergent thereon can be so significantly improved.
In accordance with the present invention a method of manufacturing a free-flowing, particulate, heavy duty synthetic organic composition comprises preparing a particulate intermediate composition comprising a detergent builder salt selected from the group consisting of phosphates, carbonates, silicates and nitrilotriacetates, and mixtures thereof, containing less than 0.5
percent of an organic anti-redeposition agent in the particles thereof and mixing said intermediate composition with from 0.1 to 5 percent of organic antiredeposition agent in powder form and from 1 to percent of a nonionic detergent or surface active agent or mixture thereof in the liquid state to produce a freeflowing, particulate, detergent composition having soil anti-redeposition properties.
To improve the method further, so that it is of increased efficiency and the product is of even better flow properties, continuous blending and spraying of the nonionic detergent will be effected in a tumbling drum and a flow-improving material, such as a clay or clacined aluminum silicate will be post-added in the drum. Also, formulations will be chosen for best flow properties. Some such formulations and methods are described in our patent applications Ser. Nos. 124,] l l; 134,324; and 203,365, mentioned previously, the disclosures of which are incorporated herein by reference.
The various compositions, methods, operations, constructions, conditions, details, uses and advantages of the invention will be apparent from the following description, taken in conjunction with the illustrative drawing of a preferred embodiment of the apparatus used to practice the method of the invention, in which drawing:
FIG. 1 is a schematic flow diagram showing the manufacture of an oversprayed spray dried detergent;
FIG. 2 is an enlarged partially sectional side elevation of tumbling apparatus employed in the practice of the invention; and
FIG. 3 is a sectional end elevation of the apparatus of FIG. 2.
In FIG. 1, aqueous detergent base or builder crutcher mix 11 is agitated in crutcher 13 by stirring means 15 which maintains it in substantially homogeneous condition. Heating means, not shown, are usually employed to raise and regulate the crutcher mix temperature so as to increase the solubilities or dispersibilities of the detergent components and to diminish the mix viscosity, so as to facilitate spraying. A high pressure pump 17, capable of producing pressures of 200 to 2,000 lbs/sq. in., pumps the crutcher mix through line 19 and spray nozzles 21 when valve 23 is opened. In spray tower 25 the sprayed droplets 27 of crutcher mix pass downwardly through an upwardly moving stream of heated air generated by burner 29, which air passes into the spray tower 25 through duct 31 and inlet ring 33. As illustrated, the heated air or combustion products result from burning gas or oil passed through nozzle 35 with air supplied by blower, 37. A vacuum is drawn on the spray tower by blower 39 and the spend drying air is removed from the tower through duct 41 and cyclone separator 43, which removes fine particles from the air at 45, allowing the cleaned air to be vented at outlet 47, after having passed through blower 39. Additional air cleaning means, such as bag-type dust separators, may also be used in conjunction with the cyclone separator but are not illustrated herein. The spray dryer illustrated is of countercurrent design and such is preferred but concurrent dryers are also useful.
The dried builder or intermediate detergent composition particles 49, usually in hollow globular or bead form, are removed from the spray drying tower by gravity and air lift 51, which is operated by vacuum generated by blower 53, and the particles travel past baffle 55 to hopper 57 for bin 58, from which they are ready to be fed to a tumbling apparatus for post spraying according to the process of this invention.
The various parts of the overspraying apparatus next described are better illustrated in enlarged FIGS. 2 and 3 than in FIG. 1. Belt feeder 59 carries spray dried base beads 49 from bin 58 under hopper 57 through hopper 61 and passage 63 into continuous tumbling drum 65. Instead of utilizing the continuously rotating drum illustrated, other continuously moving tumblers, such as twin shell blenders, may be employed. Such other tumblers or the present drum if suitably modified, may be used in batch operations. In the preferred continuous operation, the anti-redeposition agent and other adjuvants which it may be desirable to add before or at the early stages of tumbling may be fed from bin 67 by feed belt 69 through line 71 to drum 65. Materials desirably added at this time include the various anti-redcposition agents, such as sodium carboxymethyl cellulose and sometimes, extra sodium siicate, often as hydrous sodium silicate. In enzyme-containing detergents, the enzymes may be added at such points or farther down the tumbling drum.
Perfume and/or any other liquid additives which are insufficiently stable to be spray dried or which for any other reasons are desirably added after spray drying, may be forced onto the base beads through line 73 and out spray nozzle 75 or through other similar lines and nozzles. Usually, slightly farther downstream than the perfume addition nozzle or nozzles there are located the nonionic detergent overspray nozzles 79 and the overspray material, with or without additional additives mixed with it, is passed through line 77 and sprayed onto the tumbling detergent base particles. As illustrated, three such nonionic detergent spray nozzles are shown, each of which is separated from the next adjacent nozzle by from I to 2 feet. Separations may be varied, depending on the sizes of the drum, and can be from 6 inches to 3 feet. The number of nozzles is usually from one to eight. In some instances, other normally liquid, melted or dissolved components of the final product formulation may be pre-mixed with the nonionic detergent or a nonionic detergent-antifoam mixture and this may be sprayed onto the tumbling particles. After sufficient residence time in the tumbling drum, preferably in continuous operation, the treated detergent particles 81 may have other powdered additives mixed with them, usually to improve flow and reduce tackiness. Thus, a finely divided clay, talc or other suitable lubricant or flow-inducing agent, such as calcined aluminum silicate (Satintone), may be added to the tumbling drum near the downstream end thereof by feeding it from bin 83 through screw feeder 85, hopper 85 and line 89. The various screw feeds, belt feeds and pumping rates for the liquids to be mixed and sprayed are regulatable individually or may be controlled by a proportioning mechanism, not shown, which maintains the desired balances of the various materials to be charged. Thus, the entire operation may be automated.
After production of the oversprayed detergent particles 81 and dusting thereonto of flow-inducing powder or other suitable finely divided materials, if utilized, the product is removed through exit 91 and forms a bed 93 on vibratory feeder 95. This bed of material is transported by the feeder to hopper 97 past screen 99 to filling bin 101, from which it is discharged to packages 103 passing along belt 104 under filling head 105. The packages are then automatically closed, sealed, cased and shipped. Any oversize particles failing to pass through screen 99 are discharged at takeoff 100. These and other oversized and undersized particles may be re-worked or otherwise further processed to be made suitable for blending with the rest of the oversprayed detergent particles produced.
Although it is not intended to effect substantial evaporation of moisture or other volatiles in the tumbling drum 65, a slight flow of air through the drum is maintained by applying vacuum to the downstream end -thereof, as illustrated by vacuum hood 107. The hood is so formed as to exert a slight effect on bed 93 of oversprayed particles and through the bed to cause an air flow from the upstream to the downstream end of the tumbling drum. Thus, any very finely divided mist-like droplets of liquid spray which did not adhere to the detergent particles will be drawn by the vacuum through the bed 93 and deposited on the particles, if this is not completely effected in the tumbling drum. Colloidal liquid not so deposited and very finely divided solid particles are removed via line 109.
FIG. 3 shows the relative positioning of the various lines for the addition of the intermediate detergent or builder particles, sodium carboxymethyl cellulose or other resinous or gum anti-redeposition agents or other particulate additives, overspraying nonionic detergent and perfume or other liquid additives. It will be noted that nozzles 75 and 79 are so directed as to spray the liquids onto the moving particles 49, which action avoids production of large quantities of tailings due to overconcentrations of the liquids on apparatus walls or on any relatively quiescent materials near the points of spraying. Arrow 111 indicates the direction of rotation of the tumbling drum.
Detergent compositions that may be prepared by the method of this invention include the anionic detergents based on sulfated or sulfonated lipophilic groups containing a higher alkyl group, preferably a higher linear alkyl, of 10 or 12 to 18 carbon atoms. In this specification, such sulfated and sulfonated materials will be referred to generically as sulf(on)ated. They will usually be employed as alkali metal salts, preferably sodium salts, but may also be used as other water soluble salts, such as those of magnesium, calcium and aluminum, in addition to the ammonium, mono-, di-, and trilower alkyl amines and mono-, di-, and tri-lower alkanolamines, each of the alkyl and alkanol groups having from one to four carbon atoms. The sulf(on)ated anionic detergents include the linear alkyl aryl sulfonates, such as the sodium higher alkyl benzene sulfonates and the sodium higher alkyl toluene sulfonates; the higher alkyl sulfates, e.g., sodium lauryl sulfate, sodium coconut oil fatty alcohol sulfate, sodium oleyl sulfate; the sodium salts of N-methyl taurine amides, e.g., lgepon T; the water soluble sodium and potassium salts of esters of isethionic acid (lgepon A); higher fatty acid monoglyceride sulfates and sulfonates, e.g., coconut oil fatty acid monoglyceride sulfate, sodium salt; higher linear olefin sulfonates, e. g., hydroxyalkane sulfonates and alkenyl sulfonates, including mixtures of long chain (C alkenyl sulfonates, sodium salts and long chain hydroxyalkane sulfonates, sodium salts; higher alkyl ethoxamer sulfates and methoxy-higher alkyl sulfates, such as those of the formulas RO(C H O),,SO M,
wherein R is a fatty alkyl of IO or 12 to 18 carbon atoms, n is 2 to 6 and M is a solubilizing, salt-forming cation. such as alkali metal, ammonium amines and alkanolamines previously mentioned, and
wherein R and R are selected from the group consisting of hydrogen and alkyls, with the total number of carbon atoms in R and R being in the range of 10 to 18. For both types of the alkoxamer sulfate detergents mentioned the preferred compounds are those in which R is about 14 to 15 and the sum of R and R is about the same.
In the crutcher mix there may also be incorporated, if desired, a higher fatty acid soap, such as the alkali metal soaps of higher fatty acid or glyceride mixtures obtained from animal fats and vegetable oils of wellknown soapmaking types, e.g., coconut oil and tallow mixtures of respective proportions from 10:90 to :50. Such soaps, especially those of sodium, aid in producing excellent detergent base beads when employed in correct proportions with the other crutcher mix constituents and yet, do not inhibit the sorption of the nonionic detergent or surface active agent applied to such beads.
Although, the spray dried detergent intermediate composition is preferably based on an anionic detergent and inorganic builder salt or the salt alone (with the usual adjuvants), sometimes it may be desirable to have a small proportion of nonionic detergent present in the intermediate so as to allow the inclusion of higher percentages of such detergent in the final product without the necessity to spray all of such quantities onto the surfaces of the detergent intermediate beads. This may be done because if a small percentage, e.g., l or 2 percent of nonionic is spray dried with the detergent intermediate beads there will be little or no pluming from the spray tower and more nonionic can be post-added without producing a tacky product. The synthetic nonionic detergent which may be incorporated in the intermediate composition will normally be such a compound known to be especially effective for separating dirt, grease, stains and other soils from fabrics, such as cottons, polyesters, cotton-polyester blends, nylons, acrylics, rayons, woolens and other fibrous materials. Such detergents usually contain lipophilic and hydrophilic moieties, generally sufficiently in balance so that the compounds are water soluble and yet have dissolving, solubilizing and/or emulsifying effects on lipophilic soil. For satisfactory detersive activity, rather than wetting or emulsifying effects alone, the lipophilic portion of the detergent molecule will generally contain at least 10 or 12 carbon atoms and will be free or substantially free of solubilizing radicals, such as hydroxyls and -OM groups, wherein M stands for metal or salt-forming ion such as alkali metal, ammonium, amine or alkanolamine. In preferred embodiments of the invention the nonionic detergent will contain from 10 to 24 carbon atoms in the lipophilic portion thereof, from 10 to 18 of which will usually be in an alkyl group, preferably a linear alkyl. Such alkyl may be joined to an aryl, such as a phenyl, toluyl or xylyl group, but is preferably the sole lipophilic portion of the detergent molecule. In most preferred embodiments, the nonionic detergent will include a linear alkyl lipophilic moiety which is unsubstituted and which contains an average of from 12 to 15 carbon atoms, sometimes preferably averaging l4 to 15 carbon atoms. Generally, preferred alkyls will have their carbon atom contents in the narrow ranges previously mentioned for the average, with some extensions beyond these. Thus, from 10 to 18 carbon atoms may be in the higher alkyl or alkoxy portion of the molecules, preferably from 12 to 16 carbon atoms. In the poly-lower alkoxy moiety, the extent of its hydrophilic nature may be regulated by including some polypropoxy groups but these will generally be limited in number to less than one-third the number of ethoxy groups because the propoxies, when formed into a chain, are usually lipophilic. Preferably, the chain will be entirely polyethoxy and from four to 40 carbon atoms will be present in such poly-lower alkoxy chain, preferably six to 30 carbon atoms and more preferably 14 to 22 carbon atoms. Such compounds are available commercially under the trade names Neodol 45-1 1, Plurafac B-26, Alfonic l6l8-65 and Neodol 25-7.
Although not as preferable as the other nonionics already mentioned for the manufacture of the present detergent products, various other nonionic detergents used are as described in the texts Surface Active Agents and Detergents, Vol. II, by Schwarz, Perry and Berch, published in I958 by Interscience Publishers, Inc., and Detergents and Emulszfiers, 1969 Annual by John W. McCutcheon. Among such nonionic compounds are the higher alkyl phenoxy poly-lower alkoxy lower alkanols, e.g., nonyl phonoxy polyethoxy ethanol (lgepal CO-880) and balanced hydrophilic-lipophilic compounds made by the condensation, either random or block, of hydrophilid lower polyalkylene oxides or lower alkylene oxides (ethylene oxide) with lipophilic lower polyalkylene oxide or lower alkylene oxides (propylene oxides), e.g., Pluronics F-68 and L44, and various Ucons. The lower alkylene oxides are of two or three carbon atoms and the nonionic detergents that are useful may contain from 4 to I00 moles of lower alkylene oxide per mole of compound. If desired, instead of the nonionic detergents mentioned, the intermediates may include compounds of similar structure with shorter or less effectively lipophilic groups, which are generally referred to as wetting agents, rather than as detergents. Such materials are described at length in the McCutcheon reference previously mentioned.
Although not usually considered to be desirable detergent materials in the present products, in the absence of anionic detergent there may be utilized synthetic organic cationic detersive materials, such as the quaternary ammonium halides and amphoteric materials, such as the Miranols, may be employed, even in the presence of either anionic or cationic compounds, sometimes with nonionics also in the formulations. Llsts of other suitable types of cationic and amphoteric compounds are found in the cited references.
The builder salt for the anionic and nonionic, nonionic or other suitable synthetic organic detergent is preferably an inorganic silicate or a mixture of such silicates, sometimes with other builders such as the phosphates, e.g., pentasodium tripolyphosphates, tetrasodium pyrophosphate; the carbonates, e.g., sodium carbonate, sodium sesquicarbonate and sodium bicarbonate (the latter of which will usually be post-added because of instability to spray drying); and organic builders, such as the nitrilotriacetates and ethylene diamine tetraacetate, tetrasodium salt. In some compositions the proportions of phosphates and carbonates and nitrilotriacetates will be held to minirna so as to comply with requiremtnts for minimum phoshates to avoid alleged eutrophication effects and to promote safety of the product. In such instances, the contents of these materials will normally be less than 2 percent of the product. The organic builders mentioned will also often be avoided to comply with government restrictions but, if and when those restrictions are lifted, building quantities of these salts, especially the nitrilotriacetates, may be employed. In some formulations it may be desired to have present borax, borates or perborates, usually as sodium salts, but in several sections of the country boron is also objectionable, especially in those areas used for the growing of citrus fruits. Occasionally, the amounts of silicates will be minimized and another builder will be used instead.
Of the silicates, the soluble alkali metal salts, such as those of sodium and potassium are preferable and, although wide varieties of ratios of M,o;sio,, wherein M is alkali metal, have been employed, the preferred building silicates which are not objectionably alkaline are those wherein M O:SiO is between about 1:1.6 to 1:3, preferably from 1:2 to 112.7, most preferably about 12.3 -or l:2.4. The silicates used may be in granular form or preferably, when compounded with the other ingredients in the crutcher mix, are in aqueous solution, e.g., at 43.5 percent solids content.
In the addition to builder salts, filler compounds, preferably inorganic salts such as the water soluble alkali metal sulfates and chlorides, e.g., sodium sulfate, sodium chloride, sodium bisulfate, either as anhydrous salts or as hydrates, may be used. Such materials do not improve detergency but do function as bulking agents and often aid in sorbing liquid, near-liquid and tacky ingredients, so as to promote flow of the product.
In the crutcher mix or other mixture of materials employed to make the detergent base particles (such homogeneous particles may also be made by drum drying, spray cooling, vacuum flashing, evaporation and various other methods for making homogeneous compositions in particulate form) there may be present a small quantity, less than 0.5 percent, preferably less than 0.2 to 0.3 percent and most preferably 0 percent, of a soil anti-redeposition agent of the synthetic or natural gum type, such as polyvinyl alcohol, sodium carboxymethyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose, sodium alginate, polyvinyl pyrrolidone or locust bean gum. Such materials, of which the sodium carboxymethyl cellulose is preferred, aid in preventing soil from depositing on the laundry through which the wash water is being drained. They maintain the soil in finely divided colloidal form so that it is removed with the waste water. The proportion of such a gum in the detergent base bead is held low, as described, to promote sorption of the nonionic sprayed onto such beads.
The proportions of various components of the products, on a final product basis, will usually be such that IS to 50 percent of detergent builder salt, I to 10 percent of nonionic detergent or surface active agent, and from 0.5 to 5 percent of synthetic organic gum antiredeposition agent are present. When anionic detergent is used, it may be from 5 to 35 percent of the product. Generally, the proportion of moisture will be in the 1 to 20 percent range, preferably from 3 to 15 percent and often about 5 to l0 percent. Other preferred ranges are 2 to 8 percent of preferably normally solid or semi-solid nonionic detergent, preferably with from 1 or 2 to 6 percent being applied in the post-addition, most preferably with about 2 to 4 percent so applied and 2 to 6 percent in the product, to percent of 5 anionic detergent, 15 to percent of detergent builder salt, and 0.5 to 3 percent of anti-redeposition agent. In some of the compositions, especially those based on nonionic detergents and wherein it is desired to improve bead strength, from 1 to 6 percent, preferably 2 to 4 percent of sodium soap is included. The content of filler salt, may be from 5 to 65 percent, preferably from 15 to percent of the product. Such salt may be anhydrous or hydrated but the moisture content thereof, if any, will be considered as part of the moisture of the product. To promote flow properties, a slipinducing agent or flow-improver, such as finely divided clay, e.g., Satintone (calcined aluminum silicate) or product of similar formula is employed, normally to the extent of from A to 4 percent, preferably from /2 to 2 percent of the product. Of course, the final product percentages given above will determine the composi tion of the crutcher mix and the spray dried intermediate beads. Normally, the crutcher mix will contain from 30 to 80 percent water, preferably from to percent thereof.
To make the detergents of this invention there is sprayed onto a base of detergent composition in particulate form, the nonionic detergent of the mentioned type which acts to glue the powdered antiredeposition agent (usually of 100 to 200 mesh particle size but which may be as fine as 325) to the base particles and contributes curd dispersion, cleaning and solvent properties to the product. Although it is possible to spray the nonionic detergent, including additional materials melted into it or fused with it, onto various particulate bases, including granulated materials, best results are obtained when the base is in globular (spray dried) form. The spray dried beads will usually have a hollow section therein and a passageway leading from the exterior surface to an interior portion. The particle sizes of the beads or granules onto which the nonionic is sprayed will be in the range of 6 to 200 mesh, preferably 6 to 140 mesh and most preferably, 8 to 100 mesh. Of course, for best flow properties and desirable appearance, the percentage of 200 mesh or finer materials is severely restricted, usually being less than 2 percent. Particle size distribution within the ranges given can be normal, although in some cases it may be desirable to remove the finer particles from a grind, as by screening. Ordinarily, most of the particles are of 20 to mesh, less than 10 percent passes a 100 mesh and preferably less than 1 percent passes a 200 mesh seive. The lesser the proportion of fines present, the more overspray is feasible and the less overspray to be used, the less critical is the fines content.
The detergent bases may be obtained by mixing various solid components thereof and grinding or otherwide-size-reducing them and classifying or screening to the desired size ranges. Preferably, however, th detergent base particles will be made by spray drying an aqueous slurry or crutcher mix, usually at an elevated temperature, e.g., 40 or 60 to C., and an elevated pressure, e.g., 200 to 2,000 lbs/sq. in., into a spray drying tower containing moving drying gas at an elevated temperature, e.g., or to 400 C. Sizes of the droplets in the tower are approximately those of the final beads but may be initially about half such diameters, with swellings during drying causing bead enlargements and diminutions of apparent densities. The beads will have a bulk density of from 0.1 to 0.8 g./ml., preferably 0.3 to 0.8 g./ml. and their moisture contents will be from 1 to 15 percent, preferably from 3 to 15 percent and more preferably, about 5 to 12 percent.
The crutcher mix composition will preferably be mostly inorganic builder salt and anionic detergent in aqueous medium, with filler salt and minor proportions of adjuvants and sometimes very minor proportions of anti-redeposition agent and nonionic detergent. Other detergents may be present in place of the anionic and in many cases the synthetic organic detergents may be completely omitted from the crutcher mix, being replaced by organic or inorganic builder salts and inorganic filler salts.
Substantial proportions of nonionic detergents, antiredeposition agents, additional builders (silicates, hydrous silicates), flow-inducing compounds. e.g., calcined aluminum silicate, perfumes, colored detergent particles, etc., may be added to the base beads in the tumbling drum and in some cases the total amount of additives may be equal to the amount of the base (espe cially if builder and filler are post-added). However, usually less than half of such amount is employed and preferably, the materials added to base beads in the tumbling drum will be from 3 or 5 to 25 percent of the final composition.
Because the final products may'be of essentially the same composition as the spray dried beads, with only water removed and a minor proportion of materials added to them, the proportions previously recited for the products may be considered to be those utilized in the crutcher mix. Of course, in those cases wherein more substantial proportions of additives are incorporated in the formula in the tumbling drum, the proportions of base material will be considered as being modi' fied accordingly.
After drying of the detergent base beads to a mois- V ture content in the 1 to 20 percent range, usually from 2 to 15 percent, the beads will be mixed in the inclined tumbling drum, which may be at an angle of from about 2 to 8 from the horizontal, higher at the inlet end, and the spray of nonionic detergent will be applied to the moving bed of beads, using the apparatus illustrated in FIGS. l-3. The spray droplets will preferably be small in size, normally less than 2 mm. and frequently from 5 to 1,000 microns, preferably from 100 to 1,000 microns in diameters. The temperature of the spray will depend to some extent on the melting points of the nonionic compound and any diluent but will usually be in the 40 to 90 C. range, preferably 50 to 70 C. At such temperatures, the sprays are liquid and remain liquid during the period in which they are approaching the detergent beads; yet, they solidify shortly thereafter and do not formv a sticky film on the beads. The surfaces of the tumbling beads will be kept in continuous motion, as by rotating in the tube at from 3 to 50 rpm, so that new surfaces are continually presented to the liquid being sprayed onto them.
The present process allows the production of freeflowing detergent beads by a method which does not produce pollution (fuming or pluming) and which is economically feasible, with high throughputs, utilizing conventional plant equipment. In addition to making a free-flowing product, the product made is also nontacky. Lengthy aging periods are not necessary for the spray dried detergent intermediate beads before they can be treated with nonionic detergent and such aging periods are not needed before filling may be effected. With various other methods for making detergent particles containing nonionics, such aging or curing periods are required, thereby slowing production and causing tying up of storage facilities.
The various types of formulations within the present description may be varied to obtain best results. For example, mixtures of the various detergents, builders, surface active agents and anti-redeposition agents may be employed and they may be of mixed particle sizes within the ranges given. The points of addition of detergent composition components may be changed, for best processing advantages. For example, it may be found desirable to post-add some of the silicate if large quantities thereof are used, so as to improve flow properties. Similarly, flowability may be increased by increases in the phosphate or sulfate contents of the detergent beads. In some compositions, where the presence of the anionic detergent is not required, it may be omitted entirely and the spray dried beads may be substantially inorganic or organic builder salts, without organic detergents or surface active agents being present. For example, in the working examples to be given subsequently, the anionic detergent may be replaced with sodium silicate, pentasodium tripolyphosphate, sodium carbonate or sodium sulfate and in such cases, flowability will be improved even more, although, of course, the detersive effects of the anionic sulf(on)ated detergent will be lost.
It is normally preferred to mix the powdered antiredeposition agent with the spray dried beads before addition thereto of the nonionic detergent. Strangely enough, such preliminary mixing produces a product of greater flowability than is made when the antiredeposition agent powder is added after the spraying onto the intermediate of the nonionic detergent. Yet, it is possible to utilize both methods and in some circumstances, as when other adjuvants are being employed, it may be desirable to spray on the nonionic first, followed by tumbling with the finely divided antiredeposition agent powder. Then too, pre-mixes of combinations of ingredients may be utilized, either with the nonionic or the anti-redeposition agent, which is especially desirable when the materials to be added are not stable at spray drying conditions.
The following examples illustrate the invention but should not be considered as limiting. Unless otherwise mentioned all temperatures are in C. and all parts are by weight.
The above crutcher mix is prepared in a commercial heated detergent crutcher and is maintained at a temperature of about 80C. After sufficient mixing, about 5 to 15 minutes, the fluid crutcher mix has air injected into it just before spraying at the rate of 15 to 20 cubic feet per minute, to regulate spraying properties. The crutcher mix is pumped by a Triplex high pressure. pump at a pressure of 700 to 1,200 lbs/sq. in. through six l0-l0 detergent spray nozzles at the top of a commercial countercurrent spray drying tower at the rate of 20,000 to 25,000 lbs/hr. The drying air in the tower is at an inlet temperature of about 350 C. and an outlet temperature of to 105 C.
The spray dried detergent beads produced are of a density of about 0.3 g./ml., a moisture content of about 9 percent and of particle sizes substantially all within the 8 to mesh, U.S. Standard Seive Series range. Less than 5 percent of the product passes through a 100 mesh sieve. The product flows very well and is not tacky.
to 94.85 parts or the spray dried detergent powder being tumbled in a plant tumbling drum at the speed of about 15 rpm, with the drum being inclined at about 8 from the horizontal, there is added, as illustrated in the drawing, three parts of sodium carboxymethyl cellulose (65 percent active) in finely powdered form. with particles in the l00 to 200 mesh range, after which there are sprayed onto the surfaces of the tumbling particles two parts of the same semi-solid polyoxyethylated higher alkanol of the formula, in liquid state at a temperature of 50 C. The spray of the nonionic detergent is in atomized form, with the particles thereof in the 5 microns to 2 millimeters diameters range, substantially all of them being in the 10 microns to one millimeter diameter range. Perfume, to the extent of 0.15 part, is sprayed onto the product, using the apparatus shown in the drawing.
Tumbling is continued and charges of detergent beads, nonionic detergent, perfume and antiredeposition agent are continuously added, with product being taken off at the same rate, maintaining the drum about 1 1 0th full of tumbling particles. All operations are those described in the specification and all apparatuses employed are those of the drawing, although other tumbling devices may also be utilized and the sprays may be relocated.
The finished product has a bulk density of about 0.3 g./ml., flows almost as well as the uncoated beads and is as non-tacky. The screen analysis is about the same as that of the base bead, with slightly more of the larger particles and less of fines, despite the addition of the finely divided CMC. It analyzes 18 percent of the mentioned anionic synthetic organic detergent, 37 percent of sodium sulfate, anhydrous, 25 percent sodium silicate, 4 percent of the ethoxylated higher alkanol, 6 percent of soap, 2 percent of sodium carboxymethyl cellulose, active ingredient, and 8 percent of moisture.
When tested for detergency, the product is found to be an excellent detergent and the comparatively low pH, about 9.5, makes it mild enough to be employed without fear of caustic effects sometimes obtained with non-phosphate detergents utilizing sodium carbonate as a builder salt instead of the phosphate. At the mentioned pH and in the presence of the nonionic and anionic detergents, the silicate, as reported in the P. S. Grand applications previously mentioned, does not form scum in the wash water.
In a variation of the above experiment, instead of overspraying with 2 percent of the nonionic detergent (Neodol 45-1 1 a 6 percent overspray of such product is employed, on both a bead having 2 percent of the nonionic detergent in it and one having none of the nonionic detergent. As might be expected, the higher the percentage of Neodol in the overspray and the higher total percentage in the product the poorer the flow but all such products are of acceptable flow rates. That having a 6 percent Neodol overspray onto a 2 percent Neodol bead has a flow rate better than half that of the product of this example, described above. Furthermore, tackiness is not unduly objectionable. When 1 percent of calcined aluminum silicate is added to the tumbling drum in the manner illustrated in the drawing, the flow rate of this 8 percent Neodol product is improved to be approximately that of the product of the main example and the tackiness is diminished.
In the examples described the detergent beads charged to the tumbling drum or an equivalent twin shell or zig-zag blender are at room temperature, about 25 C., but in variations of the experiments, the beads are taken from the spray dryer within minutes after drying and, at a temperature of about 35 to 40 C., are processed in the drum. in both cases, a free-flowing, non-tacky product results and this is a further advantage of the present method in that it is not necessary to cool and age spray dried detergent beads to be postcoated with the nonionic detergent.
When, instead of Neodol 45-1 1, other such nonionic detergents, including Plurafac B-26, Alfonic 1618-65 or 1618-60 and Neodol 25-7 are utilized, some of which are liquids and some of which are semi-solids, similar good coating effects are produced, the products resulting are excellent heavy duty built synthetic organic detergents and they are free-flowing and nontacky. This is also the case when, instead of the sodium dodecyl benzene sulfate, sodium higher alkyl (C polyethoxy sulfate of six ethoxy groups, C olefin sulfonate, or other suitable sulf(on)ated anionic detergent of the type described in the preceding specification is used. Good products also result when the proportions of after-added anti-redeposition compound are varied over the 0.5 to 5 percent range, when the silicate and sulfate proportions are similarly varied over the ranges given and when no nonionic is utilized in the crutcher mix and from 1 to 5 percent. thereof is post-sprayed onto the tumbling product. Good results also obtain when in place of 1 percent of the sodium sulfate in the crutcher mix, there is post-added to the product 1 percent of enzyme or minor percentages of heat-unstable salts or other materials, e.g., sodium bicarbonate. In all such cases the products made have pHs of 1 percent solutions in the 8 to 10 range, preferably 8 to 9.5.
EXAMPLE 2 Following the procedure described in Example 1 there is made a product of the following final formulation:
Parts Sodium linear tridecyl benzene sulfonate 18 Sodium silicate (Na,O:SiO 1:24) 25 Sodium soap (cocoztallow 15:85) 6 Nonionic detergent 3.0 Sodium sulfate 39.8 Sodium carboxymethyl cellulose 2.0 Perfume 0.2 Water 6.0
"Neodol 45-1 l The product is made by spray drying according to the method previously described, after which the CMC is mixed in with the detergent beads and the Neodol 45-1 1 is sprayed onto them, also by the techniques previously mentioned.
The product resulting is an excellent built heavy duty laundry detergent which does not flow as well as desired but is almost completely non-tacky, with or without addition of Satintone or Cab-O-Sil (1 percent) and has a bulk density of about 0.3 g./ml. Addition of Satintone improves the flowability to good. The product is substantially all within the 8 to mesh range and has less than 1 percent material passing a 200 mesh seive.
When instead of the anionic detergent described, mixtures of equal parts of the various detergents mentioned in Example 1 are employed as the anionic detergent(s) and when Neodol 25-7 is employed in equal parts with Neodol 45-11 (I percent each), good. freeflowing, excellent detergents are also produced. especially with 1 percent clay present. The addition of up to 5 percent of various adjuvants such as fluorescent brighteners, dyes, bactericides, anti-foaming agents, antioxidants and preservatives does not adversely affect either the flowability or the detergency of the product.
When variations are made in the experiments of Examples l and 2 so as to change the proportions of materials within the ranges given in the specification and to change the processing conditions, as mentioned, good products are also produced by these feasible commercial processes. Such products are not objectionably tacky and are free-flowing so that they can be filled by automatic packaging equipment and will not cake in the box during storage. The processes described do not result in any objectionable plurning from the spray tower and air pollution is minimized by following them.
EXAMPLE 3 Sodium linear tridecyl benzene sulfonate Sodium silicate (ua osio, 112.35)
Nonyl phenol polyoxyethylene ethanol l.
(lgepal CO-880) Sodium carboxymethyl cellulose (or PVA) 3 Sodium sulfate 38 Perfume 0 Water 7 The above formula is made by the method described in Example 1 and is repeated, using a pilot plant spray dryer and a laboratory tumbling drum. in one case, pyrogenic silica (Cab-O-Sil) or calcined aluminum silicate (Satintone) flow-inducing agent is added to the extent of 1 percent of the product and in the other case none of such material is added. Both products flow well although that with the additive is freer flowing and is also non-tacky. in the formulation described, the nonionic detergent is completely post-sprayed onto the detergent particles and none at all of the sodium carboxymethyl cellulose is included-in the crutcher mix, with the total being post-added by mixing with the detergent beads before spraying onto them of the perfume and nonionic detergent.
In similar cases when the various components of the product are mixed together as dry powders (little or no spray drying effected) the product made is not as good flowing and requires larger prportions of Satintone or Cab-O-Sil (up to 2 percent) to promote flow.
EXAMPLE 4 Water 140 lbs. Sodium linear higher alkyl benzene 100 lbs.
sulfonate detergent base, 56% solids aqueous slurry Sodium sulfate, anhydrous I52 lbs. Fluorescent brightener (Stilbene No. 4) 662 grams Fluorescent brightener (ALF) l65 g. Antioxidant 68 g. Neodol 45-ll 9 lbs. l oz. Sodium silicate (Na,O:SiO, l:2.3. solids 78 lbs.
content 43.2%, aq. sol'n.) Sodium tripolyphosphate 170 lbs.
' C averaging about 875% active ingredient. the balance being about sodium sulfate and 2.5% unreactcd oil (alkyl benzene) The above components of a detergent base crutcher mix are sequentially added to a crutcher and are mixed therein for minutes to a final temperature of 185 F. The crutcher mix has a specific gravity of about l.27 when it is ready for pumping to a spray drying tower. The method followed is in accordance with the drawing except for the fact that non-vital pieces of equipment and operations have been omitted from the drawing for the purpose of simplicity and similarly, will be omitted from this description.
The crutcher mix is pumped to the spray tower by a positive pressure pump producing 800 lbs. gauge pressure at a manifold before the spray nozzle. A single spray nozzle, No. 2-l5 Whirljet, is utilized to spray the crutcher mix into the top of the 60 ft. high, 8 ft. diameter countercurrent tower. The inlet air temperature to the tower is 475 F. and the outlet temperature is 400 F. The slurry enters the spray nozzle at 180 F. Residence time in the tower is variable but it is on the order of l to 4 minutes. Product is withdrawn at the bottom of the tower and is airlifted to a bin from which it is dispensable to a mixing drum or twin shell blender. Experimentation has shown that the actions of the batch and continuous tumbling drums and twin shell blenders are substantially equivalent.
The spray dried detergent base beads, of particle sizes in the 6 to 140 mesh range, most of which is in the 8 to l00 mesh range, are found to have a moisture content of 10 percent upon charging to the tumbling apparatus. They are also of a density of about 30 lbs. per cubic foot and at a temperature of 80 F., when charged. To the continuous tumbling drum are added 96 parts of the base bead 10 percent moisture), 3 parts of Neodol 25-3, containing 0 percent moisture, 3.0 parts sodium carboxymethyl cellulose, and 0.15 part perfume. The tumbler is operated at 25 rpm. and blending takes 2.5 minutes, with the initial 30 seconds being allowed for blending the CMC with the detergent beads in the early part of the blending operation. The CMC powder is of particle sizes in the 100 to 200 mesh range. The liquid Neodol 25-3 and perfume are sprayed into the mixer so as to have particle sizes of approximately 50 to 100 microns as they are directed against a wall of falling detergent beads, utilizing 40 lbs/sq. in. gauge air pressure to th Spray Systems Inc. round spray cone atomization nozzle. After completion of mixing, the beads are withdrawn and are immediately (within 1 minute) packaged in cardboard cartons, which are sealed and sent to storage.
Subsequently, the detergent produced is checked for flow properties and tackiness by tests found to be satisfactorily indicative of the mentioned characteristics. The flow rate is found to be 62 percent, compared to the flow of a standard sand through a particular orifice. This is a good flow rate for synthetic detergents, since 55 to 74 percent is considered to be an acceptable range for detergent flows, and because the flow rate compares favorably with the untreated detergent beads containing no sprayed on nonionic surface active agent. When tested for tackiness, the product is found to be non-tacky, having a tackiness number of 0. This test is one in which detergent particles are placed in a cylindrical form approximately 5 inches high and having a cross-sectional area of about 10 square inches. A 10 pound weight is placed on the detergent, the form and weight are removed, and weights are placed on the top of the detergent cylinder resulting until it collapses. A rating of 0 indicates that the detergent beads did not adhere to each other at all despite the molding pressures applied; thus, they were not tacky. The detergent particles are of a specific gravity or bulk density about the same as that of the beads before overspraying thereon of the nonionic surface active agent.
The above-described overspraying procedure is one in which a tumbling drum like that of the drawing is used and in which the overspraying operation is continuous. However, when a batch operation is effected with the same equipment, except for the installation of baffles to maintain good mixing throughout the drum, the changing of the angle of the drum from about 3 to 0 and the more central addition of materials and the direction of overspray thereon, equally good results are obtained. Similarly, when a suitable continuous or batch twin-shell blender is employed, such results are also obtained. However, for ease of manufacture and control of product quality, the continuous drum blender is preferred.
Various other changes are made in the product formula and processing techniques and good non-tacky, free-flowing products are made, in accord with the invention. Thus, when the pentasodium tripolyphosphate is replaced with sodium carbonate a non-tacky and free-flowing detergent is made, if the CMC is tumbled in with the other ingredients in the drum, rather than being incorporated in the crutcher mix. Yet, if in the crutcher, the CMC impedes penetration of the detergent beads by the nonionic and sticky product results.
When, in addition to th Neodol 25-3 in the overspray, 3 parts of Neodol 45-] l are also present. the combined nonionic surface active agent and detergent, in solution in each other, are readily absorbed by the detergent beads and result in a free-flowing oversprayed product of improved detergency, due to its content of additional nonionic detergent. The additional detergent improves washing and whitening effects on laundry whereas the surface active nonionic is most useful in helping to solubilize oily stains on clothing washed.
Instead of Neodol 25-3 in the overspray Neodol 25-7 is used, with good results, too. To improve penetration of this thicker nonionic some of the tripolyphosphate (l0 to percent thereof) is replaced by sodium carbonate, the larger proportions being used when from 3 to 5 percent Neodol 45-] l is also present, with either The Neodol 25-3 or 25-7 as the nonionic surfactant. Such products are also free flowing. Further changes in formulations include variations in the proportions of base detergent ingredients listed, within the ranges recited in the specification. Thus, 10 to 20 percent increases or decreases in the amounts of the mentioned constitutents may be made without appreciable effects on the desirable properties of the products. Also, when some of the anionic detergent is replaced by other anionics, e.g., sodium lauryl sulfate, 80:20 tallow:coco soap or sodium alkyl sulfonate, to the extent of 2 to 3 percent replacement, the product made is free flowing and of good detergency. The same applies when Neodol 25-7 or mixtures of the surface active Neodols with Neodol 45-1 1 or other detergent nonionics of this type are in the overspray. Also, when 2 percent of the sodium tallowzcoco soap is added to the rest of the formula in the crutcher mix the product is a good detergent of non-tacky characteristics. It flows slower than the reported product but is still within the allowable free flowing range, according to the flow test results and visual observation.
A surprising observation made during the running of these experiments is that the fluorescent brightener is of appreciably more effect in the post-sprayed detergents than in controls, apparently due to being drawn nearer to the bead surface by the presence of the nonionic surfactant(s). This phenomenon is observed whether the nonionic is applied as a spray at about 80 F., as in the present case, or at higher or lower temperatures within the range specified. However, usually the temperature of the nonionics sprayed are at least 10 F. over their solidification points.
EXAMPLE 5 A detergent base bead is made according to the method described in Example 4 but with the crutcher constituents so chosen as to result in a product containing 6 percent linear tridecyl benzene sulfonate, sodium salt; 34 percent sodium tripolyphosphate; 6 percent of the described silicate and 37.85 percent sodium sulfate, all on a finished product basis. Onto such beads, containing 10 percent H O, mixed with 2 percent CMC powder is oversprayed a solution of Neodol 25-3, Neodol 45-1 1 and perfume, to result in a final product of the type within this invention, containing 3 percent Neodol 25-3, 3 percent Neodol 45-1 1 and 0.15 percent perfume. The sprayed liquid is of particle size within the 50 to 500 micron range, on the low side thereof, and the beads are of 8 to 100 mesh. Tumbling is in a twin shell blender (batch) and lasts for about 4 minutes. The nonionic overspray liquid is initially at about room temperature, 75 F., and the beads treated are at 104 F., having been recovered from the tower airlift only a couple of minutes before being oversprayed.
The product drawn off is free flowing (rating of 67 percent) and non-tacky (rating of 0). These figures are exactly the same as those for the untreated beads. The product may be packed immediately after manufacture and the packaged material is free flowing after months of storage. Bulk density of the product is 35.5 lbs/ft, compared to 36.6 lbs./ft for the starting beads. It will also be noted that the particle sizes are in the 8 to 80 mesh range, compared to the original 8 to 100 mesh.
The detergency of the product is good although the content of anionic detergent is' fairly low and that of supplementing nonionic detergent raises detergent content to less than 10 percent.
As in the preceding example, when changes are made in the formulation, such as the addition of borax, phosphate, CMC enzymes and Satintone to the tumbling drum, in the amounts mentioned in the preceding specification, good free flowing final detergent particles are the result. Similarly, when processing conditions are altered but kept within the ranges described, results are good and acceptable product is made.
EXAMPLE 6 A spray dried base bead made according to the method of Example 4, is oversprayed promptly after manufacture with mixed materials to give 3 percent Neodol 25-3, an additional 4 percent Neodol 45-1 1 and 0.15 percent perfume. The tumbling is effected in a drum of 1:2 diameter to length ratio, inclined at an angle of about 5 and rotating at 34 rpm. The liquid spray is at room temperature and the particle size is 50 to 100 microns. The detergent bead temperature is about F. Product is of a bulk density of about 0.5 g./cc., 9.7 percent moisture content, rates 59 percent in flowability and is non-tacky.
EXAMPLE 7 The experiment of Example 4 is repeated but with Neodol 25-7 used instead of Neodol 25-3. Product density is 0.5 g./cc., moisture content is 9.5 percent, flow is 64 percent and operations in the 18 ft. X 6 ft. diame ter drum, rotating at 4.5 r.p.m. proceed smoothly. The product resulting is an acceptable free flowing detergent.
The invention has been described with respect to examples and illustrations of embodiments thereof but is not to be considered as limited to them, since it will be clear to one of skill in the art how to substitute equivalents and modify the operations without departing from the spirit of the invention.
' What is claimed is:
1. A method of manufacturing a spray-dried freeflowing, particulate heavy duty synthetic organic detergent composition which comprises preparing by spraydrying a particulate intermediate composition which contains a detergent builder salt selected from the group consisting of alkali metal tripolyphosphates, alkali metal pyrophosphates, alkali metal carbonates, alkali metal silicates and alkali metal nitrilotriacetates, and mixtures thereof, and which contains less than 0.5 percent by weight of synthetic organic antiredeposition agent, and mixing said intermediate composition with from 0.1 to 5 percent by weight of a synthetic organic anti-redeposition agent in powder form, which agent is selected from the group consisting of carboxymethyl cellulose, polyvinyl alcohol, methyl cellulose, hydroxypropyl methyl cellulose, polyvinyl pyrrolidone and polymeric acrylamide and mixtures thereof, and additionally admixing thereto from 1 to 10 percent by weight of a nonionic surface active compound or mixture thereof in liquid state, which nonionic compound contains lipophilic and hydrophilic moieties in blaance so that the compounds are water soluble and have dissolving, solubilizing and emulsifying effects on lipophilic soil, which nonionic surface active compound contains from 10 to 24 carbon atoms in the lipophilic moiety thereof and four to [00 lower alkoxy groups, wherein the lower alkoxy is of two to three carbon atoms, to produce a free-flowing, particulate, detergent composition having soil anti-redeposition properties.
2. A method according to claim 1 wherein the detergent builder salt is a sodium salt, the particulate intermediate composition contains less than 0.3 percent by weight of an antiredeposition agent selected from the group consisting of sodium carboxymethyl cellulose, polyvinyl alcohol, methyl cellulose, hydroxypropyl methyl cellulose, polyvinyl pyrrolidone and polymeric acrylamide, said intermediate detergent composition is produced by spray drying of an aqueous composition containing such detergent builder salt or mixture thereof, from 0.5 to 5 percent by weight of the synthetic organic gum anti-redeposition agent, in finely divided powder form, is mixed with the intermediate detergent composition, and from 2 to 6 percent by weight of the nonionic detergent, which is normally solid or semi-solid, is sprayed onto the intermediate detergent composition and is cooled thereon to form a freeflowing particulate synthetic detergent composition having soil anti-redeposition agent held thereto.
3. A method according to claim 2 wherein the mixing of the intermediate detergent composition particles and the finely divided synthetic organic gum antiredeposition agent powder and the spraying onto the mixture of the nonionic detergent is continuous, the detergent particles and anti-redeposition agent are at about room temperature, the nonionic detergent is at an elevated temperature in the range of 40 to 90 C. and the temperature difference and the quantities of detergent composition constituents are such as to cool the nonionic detergent to solid or semi-solid form due to heat being extracted therefrom by the intermediate detergent composition particles and the antiredeposition agent powder.
4. A method according to claim 2 wherein the freeflowing particulate synthetic detergent composition comprises by weight from l5 to 50 percent of the detergent builder salt, 5 to 65 percent of sodium sulfate, 2 to 8 percent of the nonionic detergent, 0.5 to 5 percent of the synthetic organic anti-redeposition agent and 3 to percent of moisture, spray drying of the intermediate detergent composition is from a crutcher mix containing from to 65 percent by weight of water, none of the anti-redeposition agent and no more than a proportion of the nonionic detergent which results in a final composition content of 2 percent by weight of said crutcher-mix derived nonionic detergent, the nonionic detergent sprayed onto the intermediate detergent composition is a higher alkoxy poly-lower alkoxy alkanol in which the higher alkoxy is of 12 to [8 carbon atoms and the poly-lower alkoxy alkanol contains three to 15 ethoxy groups, the temperature of the nonionic detergent when it is sprayed onto the surfaces of the particles of intermediate detergent composition and anti-redeposition agent is from to 90 C. at which temperature the nonionic detergent is liquid, and said spraying is conducted while tumbling the spray dried particles to present new surfaces thereof to the liquid being sprayed onto them.
5. A method according to claim 4 wherein the detergent builder salt is selected from the group consisting of sodium silicate of Na- O:SiO ratio in the range of 1:16 to l :3 and mixtures of at least 5 percent by weight thereof, on a final product basis, with the other detergent builder salt or salts of claim 4, the sprayed intermediate detergent composition particles and the final detergent composition particles are substantially all within the 6 to 140 mesh, US. Standard Sieve Series range, the particles of anti-redeposition agent are of a size in the l00 to 200 mesh range, the spray of the nonionic detergent is at a temperature of to C. and the particles thereof in atomized form are in the 5 micron to 2 millimeters diameter range, and the powdered anti-redeposition agent is mixed with the spray dried intermediate detergent composition beads before spraying the nonionic detergent onto the surfaces of the particles of such mixture.
6. A method according to claim 5 wherein the sodium silicate is of Na O:SiO ratio in the range of I12 to 122.7, the spray dried intermediate detergent composition particles contain 5 to 35 percent by weight of a water soluble anionic sulf(on)ate synthetic organic detergent salt having a higher linear alkyl chain therein. the anti-redeposition agent is sodium carboxymethyl cellulose, the nonionic detergent sprayed onto the sur faces of the mixture of anti-redeposition and spray dried intermediate detergent composition particles is substantially anhydrous and is semi-solid at room temperature, and after the mixing of the intermediate detergent composition and anti-redeposition agent particles and spraying thereon of the nonionic detergent, there is blended with the resulting product from A to 4 percent by weight of a material selected from the group consisting of finely divided clay and pyrogenic silica to improve the flow properties of the detergent composition.
7. A method according to claim 6 wherein the sodium silicate is of Na O:SiO ratio of about 112.35, the anionic detergent is sodium linear higher alkyl benzene sulfonate in which the higher alkyl group is of 12 to 14 carbon atoms, the spray dried intermediate detergent composition particles and the final product particles contain from i to 6 percent of sodium higher fatty acid soap, spray dried from the same slurry as the other constituents of the intermediate detergent composition particles, the nonionic detergent is one in which the higher alkoxy is of 12 to 15 carbon atoms and which contains from 7 to l5 ethoxy groups, and the flowimproving agent is calcined aluminum silicate and from /2 to 2 percent thereof is present in the final composition.
8. A method according to claim 7 wherein the mixing of the intermediate detergent composition particles and the finely divided synthetic organic gum antiredeposition agent powder and the spraying onto the mixture of the nonionic detergent is continuous, the detergent and anti-redeposition agent are at about room temperature, the nonionic detergent temperature and the temperature difference and quantities of detergent composition constituents are such as to cool the nonionic detergent to solid or semi-solid form due to heat being extracted therefrom by the intermediate detergent composition particles and the anti-redeposition agent powder on them, the continuous mixing and spraying are effected in a tumbling drum and flowimproving agent is added near the end of passage of materials through the drum.
9. A method of manufacturing a free-flowing, particulate heavy duty synthetic organic detergent composition which consists essentially of preparing a particulate intermediate composition which contains a detergent builder salt selected from the group consisting of alkali metal tripolyphosphates, alkali metal pyrophosphates, alkali metal carbonates, alkali metal silicates and alkali metal nitrilotriacetates, and mixtures thereof, and which contains less than 0.5 percent by weight of a synthetic organic anti-redeposition agent selected from the group consisting of carboxymethyl cellulose, polyvinyl alcohol, methyl cellulose, hydroxypropyl methyl cellulose, polyvinyl pyrrolidone and polymeric acrylamide and mixtures thereof, and mixing said intermediate composition with from 0.1 to percent by weight of a synthetic organic anti-redeposition agent in powder form, which agent is selected from the group consisting of carboxymethyl cellulose, polyvinyl alcohol, methyl cellulose, hydroxypropyl methyl cellulose, polyvinyl pyrrolidone and polymeric acrylamide, and from 1 to percent by weight of a nonionic surface active compound or mixture of such compounds in liquid state, which nonionic compounds contain lipophilic and hydrophilic moieties in balance so that the compounds are water soluble and have dissolving, solubilizing and emulsifying effects on lipophilic soil, which nonionic surface active compounds contain from 10 to 24 carbon atoms in the lipophilic moieties thereof and four to 100 lower alkoxy groups and wherein the lower alkoxy is of two to three carbon atoms.
10. A method according to claim 9 wherein the par ticulate intermediate composition is made by spray drying a crutcher mix of, by weight, about 1,915 parts of sodium linear dodecyl benzene sulfonate, about 3,067 parts of an about 43.5 percent solids aqueous sodium silicate solution wherein the Na OzSiO ratio equals about 112.35, about 1,896 parts of anhydrous sodium sulfate, about 107 parts of RO(CH CH O),,CH C- H OH, wherein R is primary alkyl of about 14 to 15 carbon atoms and n equals about l0, about 469 parts of an about percent solids sodium coconut-tallow kettle soap wherein the coconut-tallow ratio is about 20:80 and about 491 parts of water to produce spray dried detergent beads of a density of about 0.3 gram/- milliliter, a moisture content of about 9 percent and a particle size of about 8 to mesh, US. Standard Sieve Series, with less than about 5 percent of the product passing through a 100 mesh sieve, and tumbling such product in a tumbling cylinder inclined at an angle of about 8 from the horizontal at a speed of about 15 revolutions per minute, admixing with the spray dried detergent powder while it is being tumbled about 3/94.85 of the weight thereof of sodium carboxymethyl cellulose of about 65 percent activity, in finely divided form, with particles in the 100 to 200 mesh range and. after mixing thereof, spraying onto the surfaces of the tumbling particles about 2/94.85 of the weight of the spray dried detergent powder of RO(CH C- H O),,CH CH OH in liquid state at a temperature of about 50 C., in atomized form with particles thereof in the 5 microns to 2 millimeters diameters range, with substantially all of the particles being in the 10 microns to l millimeter diameter range, while maintaining the drum about 1 10 full of tumbling particles during operation thereof, to produce a product which contains, by weight, about 18 percent of the sodium linear dodecyl benzene sulfonate, about 37 percent of sodium sulfate, about 25 percent of sodium silicate, about 4 percent of ethoxylated higher alkanol, about 6 percent of soap, about 2 percent of sodium carboxymethyl cellulose, as active ingredient, and about 8 percent of moisture, which is free-flowing, nontacky and of a bulk density of about 0.3 g./ml.