US 3886098 A
A free flowing particulate detergent composition containing a nonionic detergent is made by spray drying inorganic salt-containing base particles which have in their composition sodium carbonate, sodium bicarbonate or sodium sesquicarbonate, a limited amount of sodium silicate and limited amounts, if any, of higher alkyl benzene sulfonate detergent, nonionic detergent, sodium carboxymethyl cellulose and other detergent composition materials which adversely affect sorption of nonionic detergent by the base particles, and distributing over the surfaces of the particles, as by spraying, a liquid poly-lower alkoxy lower alkanol-containing nonionic detergent compound. Such spraying is normally effected continuously in a tumbling drum over a short period of time and preferably, the base particles are freshly charged from a spray drying tower. Sodium carboxymethyl cellulose, other organic gum anti-redeposition agents and other detergent constituents may be tumbled in with the detergent base beads without adversely affecting the sorption of the liquid nonionic detergent by the beads.
Claims available in
Description (OCR text may contain errors)
United States Patent DiSalvo et al.
1*May 27, 1975  Inventors: Walter A. DiSalvo, North Arlington;
Edward J. Kenney, Bernardsville; Frank R. Smith, Jr., Plainfield, all of NJ.
 Assignee: Colgate-Palmolive Company, New
[ Notice: The portion of the term of this patent subsequent to Sept. 20, 1988, has been disclaimed.
 Filed: Apr. 15, 1971  Appl. No.: 134,324
Related US. Application Data  Continuation-in-part of Ser. No. 124,11 l, March 15,
1971. Pat. Nov 3,838,072.
 US. Cl. 252/540; 252/135; 252/531; 252/535; 252/539  Int. CL... Clld l/22;C11d 1/83;C11d 11/00  Field of Search 252/89, 99, 135, 531, 535, 252/539, 540,550,554, 558,559
 References Cited UNITED STATES PATENTS 1,898,707 2/1933 Baker 252/135 X 2,264,103 6/1936 Tucker 210/23 2,623,856 5/1948 Sanders 252/135 2,874,123 9/1954 Schaafsma et al. 252/99 3,306,858 2/1967 Oberle 252/99 3,329,616 7/1967 Feierstein et a1. 252/135 X 3,461,074 8/1969 Schwalley 252/109 3,501,408 3/1970 3,515,672 6/1970 Reinish et al. 252/109 3,519,570 7/1970 McCarty 252/135 3,590,001 6/1971 Taylor et al. 252/539 X 3,597,361 8/1971 Sumner 252/558 3,630,920 12/1971 Freifeld et al. 252/90 3,700,600 10/1972 Nagel et a1 252/99 FORElGN PATENTS OR APPLICATIONS 525,514 8/1940 United Kingdom 1,191,356 5/1970 United Kingdom 918,499 2/1963 United Kingdom 164,603 8/1955 Australia 205,479 1/1957 Australia 491,125 3/1953 Canada 511,415 3/1955 Canada 540,252 4/1957 Canada 586,622 11/1959 Canada Primary Examiner-P. E. Willis, Jr. Attorney, Agent, or Firm-Herbert S. Sylvester; Murray M. Grill; John J. Tomaszewski  ABSTRACT A free flowing particulate detergent composition containing a nonionic detergent is made by spray drying inorganic salt-containing base particles which have in their composition sodium carbonate, sodium bicarbonate or sodium sesquicarbonate, a limited amount of sodium silicate and limited amounts, if any, of higher alkyl benzene sulfonate detergent, nonionic detergent, sodium carboxymethyl cellulose and other detergent composition materials which adversely affect sorption of nonionic detergent by the base particles, and distributing over the surfaces of the particles, as by spraying, a liquid poly-lower alkoxy lower alkanolcontaining nonionic detergent compound. Such spraying is normally effected continuously in a tumbling drum over a short period of time and preferably, the base particles are freshly charged from a spray drying tower. Sodium carboxymethyl cellulose, other organic gum anti-redeposition agents and other detergent constituents may be tumbled in with the detergent base beads without adversely affecting the sorption of the liquid nonionic detergent by the beads.
12 Claims, 3 Drawing Figures MANUFACTURE OF FREE FLOWING PARTICULATE DETERGENT COMPOSITION CONTAINING NONIONIC DETERGENT This is a continuation-in-part of application Ser. No. 124,111, filed Mar. 15, 1971 now U.S. Pat. No. 3,838,072.
This invention relates to the manufacture of free flowing particulate detergent compositions which contain a nonionic detergent constituent. More particularly, it is of methods useful for making such compositions, which are of improved detergency, whichinclude overspraying certain nonionic detergents or mixtures of such detergents onto detergent base particles, such as those which may be made by spray drying.
In accordance with the present invention, a method of manufacturing a particulate detergent composition comprises making inorganic salt-containing base particles comprising, on a detergent composition weight basis, at least percent of sodium carbonate, sodium bicarbonate or sodium sesquicarbonate, at least 5 percent and less than 30 percent, generally less than 15 percent of sodium silicate, less than 15 percent of soluble higher alkyl benzene sulfonate detergent, less than 4 percent of nonionic detergent and less than 0.5 percent of sodium carboxymethyl cellulose, with the components of the base particles being such that the subsequently mentioned nonionic detergent is readily sorbed thereby, and distributing over the surfaces of the particles, while they are in motion, from 2 to percent by weight of the detergent composition of a poly-lower alkoxy lower alkanol-containing nonionic detergent compound wherein the poly-lower alkoxy lower alkanol is of 20 to carbon atoms. For best detergency, the compositions made will include anionic synthetic organic detergent, nonionic synthetic organic detergent and pentasodium tripolyphosphate but the inventive method also lends itself very well to the manufac ture of products wherein the phosphate is substantially decreased in amount or is omitted entirely, and of others in which the anionic detergent is also omitted. Within the invention is the manufacture of strong sorptive essentially inorganic salts beads, suitable to be post-sprayed with nonionic detergent or for use in formulating detergent compositions. The products, as well as the methods for their manufacture, are also within the invention.
In useful embodiments of the invention a detergent of the base is a water soluble higher alkyl benzene sulfonate detergent, present in a quantity less than that which prevents sorption of a subsequently oversprayed nonionic detergent, the nonionic detergent of the base, if present, is present in limited quantity and is a higher alkoxy polyJower alkoxy lower alkanol detergent, sodium silicate of an Na O:SiO ratio of between 1:1.6 and 1:3.4 is present in amount sufficient to strengthen the base bead but not to prevent sorption of the oversprayed nonionic detergent, and the carbonate is sodium carbonate, useful to aid in sorbing the nonionic detergent overspray and, in the absence of the tripolyphosphate, acting to build the detergent composition and thereby improve its washing power. Of great importance in the present invention is the use of sodium carbonate in the base particles, usually of spray dried, substantially inorganic salt composition, since with the present detergents and in the formulas described, the base beads quickly and sufficiently sorb the nonionic overspray material to allow it to be free flowing soon after completion of the relatively fast overspraying operation. Thus, a product may be packaged shortly after manufacture, using high speed filling machinery, without fear of laziness of flow preventing satisfactory movement through the filling machinery. The product made, in addition to being free flowing, is essentially non-tacky. It is of good spherical particle appearance, satisfactory white or colored and is especially useful as a home laundry washing product.
To maintain the product free flowing and non-tacky, the amounts of synthetic detergent, moisture, synthetic organic gum anti-redeposition agent, sodium sulfate and pentasodium tripolyphosphate in the detergent base will usually be limited, if present at all. The base is best spray dried and most of the nonionic detergent or substantially all of it will be oversprayed as liquid onto the surfaces of the spray dried base particles while they are in tumbling motion, at a time usually shortly after the completion of spray drying.
By the present method there may be added to detergent compositions liquid or near liquid nonionic detergents which significantly improve the washing properties of the compositions and still allow them toremain free flowing and of acceptable non-tacky properties. When the detergent particles are relatively light in weight, usually ofa bulk density of 0.3 to 0.6 g./cc., and of readily soluble hollow globular form, such as are produced by spray drying, significant improvements are made in production methods over processes wherein nonionic detersive compounds are present in the crutcher mix and are spray dried with the other ingredients. In such comparative spray drying operations the nonionics tend to plume and often are lost from the spray dryer as aerosols. This can cause air pollution and represents an economic loss. Additionally, changes in the amounts of nonionics plumed out of the tower causes variations in the analyses of the final products. By following the present methods, greater tower throughput is obtainable and formulating flexibility is realizable. Various materials may be added to the de scribed compositions in the tumbling drum, whereby modifications of the product may be made over those which are available by corresponding additions to the crutcher mix. An additional useful feature of the present invention is in the improved appearance of the product made, compared to products of similar formulations wherein granular materials are tumbled together or in which spray drying alone is utilized. Details of such improvements will be given later.
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 thereof, 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 eievation of the apparatus of FIG. 2.
In FIG. ll, aqueous detergent base 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 oil passed through nozzle 35 with air supplied by blower 37. A vacuum is drawn on the spray tower by blower 39 and the spent 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 dried detergent 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 to make the product 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, 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 antiredeposition agents, such as sodium carboxymethyl cellulose, extra sodium silicate and sometimes, additional sodium tripolyphosphate. 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 down stream than the perfume addition nozzle, the nonionic detergent overspray material is similarly passed through line 77 and nozzles 79. As illustrated, three such spray nozzles are shown, each of which is separated from the next adjacent nozzle by from one to two feet. Separations may be varied, depending on the sizes of the drums, and can be from 3 inches to 3 feet. The number of nozzles may be from one to six. In some instances the perfume and other liquid or soluble components of the formulation may be pre-mixed with the nonionic detergent and may be sprayed with it rather than through separate nozzles. After a 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 87 and line 89. The various screw feeds, belt feeds and pumping rates for the liquids to be sprayed are regulatable individually or may be controlled by a proportioning mechanism, not shown, which maintains the desired balances of the various material 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, 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 automatiically 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 reworked 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 to be oversprayed onto 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 detergent base 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 and 79 are so directed as to spray the liquids onto the moving particles 49, which action avoids production of large quantities of tailings dueto 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.
In making the base detergent composition it is highly preferred to employ a spray dryer, either countercurrent or concurrent, such as are known in the detergent industry to be useful for the production of light weight and substantially globular detergent beads, which preferable are also hollow. Other apparatuses may be used providing that the base particles produced are of desired particle size, shape, density and flow characteristics. However, it is not desirable to use agglomerated particles, made by mere mixing of finely powdered detergent composition constituents in the presence of a binding agent, nor is it preferred to employ dry mixtures of ground detergent composition ingredients.
Spray drying is effected by crutching an aqueous crutcher mix of the base detergent composition, which may be esentially inorganic salt but often will include a synthetic organic detergent, preferably an anionic detergent, which term includes the usual higher fatty soaps. Of the anionic detergents the higher alkyl benzene sulfonates, especially the water soluble salts of linear higher alkyl benzene sulfonates, e.g., the alkali metal salts, of which sodium linear higher alkyl benzene sulfonate is preferred, will be employed. However other anionic detergents and minor proportions of nonionic detergents, providing that they do not cause pluming in the spray tower, may also be present. Such compounds are well known in the detergent art and are described at length at pages 25 to 138 of the text, Surface Active Agents and Detergents, Vol. II, by Schwartz, Perry and Berch, published in 1958 by Interscience Publishers, lnc. Among the important anionic compounds so listed are the higher alkyl sulfates, the higher fatty acid monoglyceride sulfates, the higher olefin sulfonates, the higher alkyl sulfonates, the sulfated phenoxy polyoxythanols, the branched higher alkyl benzene sulfonates and the higher fatty acid soaps. Usually, such compounds or derivatives are employed as water soluble salts and generally these are alkali metal salts, e.e., sodium salts, of the mentioned compounds. Also, the higher alkyl or fatty groups will generally be of 12 to 18 carbon atoms. Of the nonionic detergents, those are preferred which are hydroxylcontaining linear polymers of lower alkylene oxides and are normally liquid or semi-solid at room temperature. These include condensation products of higher fatty alcohols with polyoxy-lower alkylene glycols, such as Neodol 45-11, Plurafac 13-26 and Alfonic 1618-65. Also useful are the block copolymers of propylene glycol, propylene oxide and ethylene oxide, such as the Pluronics, e.g., Pluronic L-44, and the middle alkyl phenyl polyoxyethylene ethanols, such as those sold as Igepals. Most of these compounds are not as good in the present detergent products as the anionics because they usually plume objectionably when spray dried, and can cause environmental mist problems when present in larger proportions in the base product. Therefore, they will be present in minor proportions, which will generally be less than half the content of the organic detergent component of the base.
The linear higher alkyl benzene sulfonates will normally be of l2 to l5 carbon atoms in the alkyl groups, preferably of 13 or about 13 carbon atoms and the linear alkyl will be substantially terminally joined to the phenyl group. However, a minor proportion thereof may be joined to the 2- or 3-carbon but generally the amount thereof will be less than 30 percent and most of that will be joined on the 2-carbon. Although small quantities of such soluble sulfonates of metals other than sodium may be present, such metals normally will be minor proportions of the salt-forming metal. it will usually be preferred to employ the sodium higher linear alkyl benzene sulfonate as the sole anionic detergent constituent of the base beads, since it is a good and acceptably biodegradable detergent, but it may sometimes be desirable to mix it with other anionics for specific purposes. For example. small proportions of soap, e.g., the sodium salt of an 80:20 or 85:15 tallowcoconut oil fatty acids mixture, may be present.
The greater part of the solids content of the crutcher mix is of inorganic salts, principally as builders or fillers for the detergent. An important builder salt constituent of this type is sodium silicate, although other alkali metal silicates may also be used. Of the sodium silicates which are employed, those having an Na O:SiO ratio of from 1:1.6 to 1:3.4 are generally useful, either as the entire silicate content or a part thereof. Silicates of Na OzSiO ratio of 1:2 to 1:3 are preferred and of them those of ratios of 1:2 to 1:25, specifically 1:2.3, are presently most preferred, although 1:2 silicates may be most used in the future. These silicates have building properties, add desired alkalinity, are anti-corrosive and are suitable for producing good crutcher mixes and stronger detergent beads. Other useful builders include pentasodium tripolyphosphate and tetrasodium pyrophosphate. Trisodium nitrilotriacetate is a good builder, if environmentally acceptable, but its content should be minor because of a tendency to counter sorption of the nonionic overspray. Additional compounds which serve as builders, usually most effective in the absence of phosphates, are borax, sodium carbonate, sodium bicarbonate and sodium sesquicarbonate. A good filler salt is anhydrous sodium sulfate and sodium chloride may sometimes also be employed.
Various other constituents and adjuvants may be present in the crutcher mix or may be post-added, including sanitizers, e.g., trichlorocarbanilide, coloring agents, e.g., dyes and pigments, foam improvers, foam depressants, fungicides, anti-oxidants, stabilizers, chelating agents, optical bleaches or fluorescent brighteners, soil suspending agents and soil anti-redeposition agents. Of the foregoing adjuvants those of most importance to the present invention, especially with respect to ready operativeness of the method and unexpected improvements in the products, are the antiredeposition agents, including; natural and synthetic organic gums or resinous materials which aid in maintaining the removed soil and other constituents of a detergent wash water in suspension so that they are not deposited on the laundry as the rinse water is drained through it. Such compounds include sodium carboxymethyl cellulose, polyvinyl pyrrolidone, polyvinyl alcohol and similar agents known in the art. The fluorescent brighteners are members of a well-known class in the detergent art and usually are reaction products of cyanuric chloride and the disodium salt of diamino stilbene disulfonic acid, benzidine sulfone disulfonic acids, amino coumarins, diphenyl pyrazoline derivatives or naphthotriazoly stilbenes. Such materials are described in the article Optical Brighteners and Their Evaluation by Per S. Stensby. a reprint of articles published in Soap and Chemical Specialties in April, May, July, August and September, 1969, especially at pages 3-5 thereof. They include cotton brighteners, polyamide brighteners, polyester brighteners and bleach'stable brighteners of the types mentioned, such as those sold as Stilbene No. 4, Calcofluor White ALF (American Cyanamid), SOF (Ciba), Blancophor PD (GAF) and Tinopal RBS (Geigy). These are of complex structures. For example, the formula of Stilbene No. 4 is disodium 4,4'-bis-(4-21nilin0-6-morpholine-s-triazin-2-ylamino) -2,2'-stilbene disulfonate. Yet. despite the complexities of their structure and their differences, the brighteners act to whiten the detergent particles made according to this invention.
The base head composition will depend to some extent on the type of final detergent product that it is intended to make. Thus, where making a product of excellent cleaning power is most important there will often be present therein significant quantities of pentasodium tripolyphosphate or other phophate builders, with an anionic detergent, such as the sodium salt of linear higher alkly benzene sulfonic acid. Although the phosphate may be post-added, it will generally be preferred to spray dry a significant proportion of, it not most or all of it, in the beads. Small quantities of nonionic supplementing detergents may also be present in the crutcher mix. When large proportions of phosphates may not be used in detergents, the quantities thereof may be approximately halved and other inorganic salts may be employed for their building or filler effects. Thus, with less phosphate, more silicate, carbonate and sulfate will usually be present. When phosphates are eliminated entirely, the amounts of carbonates and filler salts may be further increased to make up for its absence. It has been found that silicate content of the crutcher mix should not be increased over about 30 percent to avoid having the beads of low sorptive effect with respect to the nonionic detergent applied to them. In those instances where detergent application is by overspraying, ratther than by incorporation in the crutcher mix and wherein neither phosphates nor anionic surface active agents are to be present in the base beads, the crutcher mix may almost entirely of inorganic salt, principally sodium carbonate (sodium sesquicarbonate and sodium bicarbonate may be employed, too), with an allowable proportion of sodium silicate, which improves the strength of the spray dried carbonate beads. Depending on which type of formulation is being made, proportions of constituents will be regulated accordingly.
The proportions of the various components in the crutcher mix from which the spray dried bead is produced are regulated so as to obtain a bead on which the nonionic surface active or detergent overspray may be deposited and in which it will be sorbed without causing the production of sticky, tacky or poorly flowing beads. The crutcher mix will usually comprise from 25 to 75 percent solids, preferably from 50 to 70 percent, with the balance being mostly, almost entirely or only water. The proportions of various crutcher mix constituents will be such as to result in detergent products having the compositions given below. Percentages of constituents calculated on a detergent product basis are considered to be more convenient to use than percentages based on either the crutcher mix or the spray dried base beads, which would require re-calculations to determine concentrations in the product. Of course, the products can be re-formulated with other materials to make still more end or final detergent products. Thus, colored detergent or inorganic salt particles may be blended in with the products to produce dotted effects or the products can be diluted with filler particles to produce detergents of varying active ingredient concentrations.
The quantity of silicate employed will generally be from to 50 percent in the final product and about 5 to percent of soluble sodium silicate is acceptable in the crutcher mix. The remainder is usually post-added but when its solubility can be retarded, as by late addition to the crutcher mix, little agitation, low crutcher temperature, large particle size and temporary coating with other materials, or any suitable combination of these, to prevent dissolving in the crutcher mix, 1 to 15 percent of a hydrous sodium silicate may be employed in the crutcher, together with the soluble silicate, so that the total silicate therein does not exceed about 30 percent and the soluble silicate is from 5 to 15 percent. The hydrous silicate used may be made by spray drying an aqueous solution of sodium silicate of a suitable ratio of from about 111.8 to 122.5 Na O:SiO with, preferably about a 1:2 ratio, to a moisture content of about l0 to 25 percent. Although the use of such a hydrous undissolved silicate in the crutcher allows a higher silicate content in the product and avoids the use of metering equipment to add silicate in the tumbling apparatus in which overspraying takes place, because of the need to carefully watch the crutching operation to prevent any solubilization of more than 15 percent of sodium silicate, it will sometimes be preferred to post-add silicate, rather than to employ the temporarily insoluble material in the crutcher. With respect to the soluble silicate in the crutcher mix, 12 percent is a preferred limit and l0 percent is most useful in the spray dried base. At 5 to 15 percent concentration in the spray dried base beads the silicate exerts a significant building effect and strengthens the bead but does not inhibit sorption of the nonionic detergent of the overspray so as to produce a poorly flowing or tacky product. Use of more than about 15 percent of soluble sodium silicate in the crutcher mix causes a sig-v nificant lumping of the base beads and a decrease in flowability of the oversprayed particles and therefore, is to be avoided. When other consitutents which have negative effects on flowability or non-tacky properties of the product are also present, the proportion of soluble sodium silicate will usually be decreased further, as to 10 percent or 8 percent. Below 5 percent content thereof its building properties and contribution to increased particle strength are not substantial. An additional 20 percent of silicate, over the 30 percent mentioned, may be present in the final product, if postaddition of silicate is practiced.
Although the silicate content may usually be varied over the 5 to 15 percent range for a variety of detergent compositions of this invention, the concentrations of the various other, more significant components of the detergent base beads utilized will depend more on the desired end properties of the compositions and the types of compositions. By types of composition is meant the phosphate content, high, low or medium, and none, and the organic detergent content. Thus, when phosphate content varies from 0 to 50 percent, usually being from 15 or 20 to 50 percent, the contents of carbonates, sulfate and other builder adjuvants will be adjusted accordingly. For a high pentasodium tripolyphosphate composition, one having from 25 to 50 percent of the tripolyphosphate, the proportions of other constituents can be from 5 to 10 percent of sodium linear higher alkyl benzene sulfonate, 8 to 13 percent of soluble sodium silicate, 12 to 40 percent sodium sulfate, 5 to 40 percent sodium carbonate (the proportion of carbonate to sulfate being at least 1:3), 5 to 15 percent moisture and from 0.1 to 2 percent of a synthetic organic fluorescent brighhtening compound. The foregoing materials are generally present in the base beads made but the percentages are on a final composition basis. Such base beads, like, the other described herein, include less than 0.5 percent of sodium carboxymethyl cellulose and usually less than 4 percent of nonionic detergent, preferably to 3 percent thereof and most preferably 0 percent. Such a detergent is usually a higher alkoxy poly-lower alkoxy lower alkanol nonionic detergent. Generally broader ranges of constituents, for phosphate-containing formulas having 15 to 50 percent of the phosphate include from to 12 or percent of sodium linear higher alkyl benzene sulfonate of 12 to 15 carbon atoms, 0 to 3 percent of the nonionic detergent, 5 to 75 percent of sodium carbonate, 5 to 30 percent of the sodium silicate of Na OzsiO ratio of 1:2 to 1:3, and 2 to 18 percent moisture, in the base beads. In compositions which may be devoid of phosphates but still include anionic detergent, from 5 to 12 percent of sodium linear higher alkyl benzene sulfonate may be present, with 0 to 3 percent of the nonionic detergent, 5 to 83 percent of sodium carbonate, 5 to 25 percent of sodium silicate, but not more than 15 percent water soluble, and 2 to 15 percent of moisture. In preferred embodiments of such compositions, there is no nonionic detergent and no sodium carboxymethyl cellulose present in the crutcher and the sodium sulfate content is from 15 to 40 percent. When the base beads comprise principally sodium silicate and sodium carbonate, bicarbonate or sesquicarbonate or mixtures thereof, the silicate will usually be from 5 to 30 percent, with no more than 15 percent being water soluble, the carbonate will be from 40 to 87 percent, adjuvants will comprise 0 to 5 percent and moisture will be 2 to 15 percent from the base. In some preferred processes and compositions the sodium carbonate content will be from 40 to '70 percent. On a base bead basis, 70 to 95 percent may be sodium carbonate and 5 to 30 percent sodium silicate. It has been found that up to about percent of sodium citrate can be substituted in the various formulas for phosphate, sulfate and to an extent, for carbonate and silicate. In such formulations from 5 to 20 percent of the citrate is useful. The sodium citrate performs some builder functions but is not as effective in this respect as the phosphates. Among other useful builders that may be employed is sodium dioxyacetate, in amount like that mentioned with respect to the citrate. The inorganic builders include borax, usually from 5 to percent and preferably from 5 to 15 percent of the composition. NTA may be utilized generally to the extent of 5 to 20 percent, but will be omitted in present formulations, in compliance with government recommendations. Among the fillers or extenders, in addition to the sodium sulfate, up to 15 per cent and preferably less than 8 percent of sodium chloride may be used. In the above description various compounds are referred to as builders although they may have only a fraction of building effects of the tripolyphosphates, because, in the absence of the phosphates, such materials are relied upon to improve washing action.
The synthetic organic detergent component will usually be from 5 to 15 percent of the product and is preferably the mentioned sodium linear alkyl benzene sulfonate. The content of such detergent compound should generally not exceed 20 percent of the product, nor be less than 5 percent thereof to have any significant detersive effect. Other anionic or nonionic detergents may be used to supplement or partially replace the alkyl benzene sulfonate but normally such total content of other synthetic detergent (s) will not exceed the amount of sodium alkyl benzene sulfonate present in the crutcher mix. Genrally, the amounts of supplementing detergent, if present at all, will be less than 10 percent. For example, from 0.1 to 5 percent of soap may be used, or 2 to 5 percent of sodium higher alkyl sulfate, or from 0.1 to 4 percent, preferably 1 to 2 or 3 percent, of nonionic, if present. The contents of various adjuvants in the base beads will usually be limited to about 15 percent of the product and generally will be less than 10 percent thereof, preferably less than 5 percent. The content of anti-redeposition agents, e.g., CMC, will be held as low as feasible in the crutcher because these materials counter sorption of the nonionic overspray. Usually the maximum proportion of such anti-redeposition agent in the base beads will be about 0.5 to 1 percent, preferably about 0.5 percent and desirably will be 0.2 percent or less. when greater quantities of CIVIC or other anti-redeposition agent are to be present, they may be added. to the tumbling drum in proportions up to 6 percent, since it has been found that such additions do not prevent sorption of the overspray nonionic detergent. It is highly preferable that all the CMC or other anti-redeposition agent be tumbled into the detergent formulations, rather than be spray dried with it. If bleaches, such as sodium perborate, are present, the content thereof will usually be from 1 to 30 percent, with some or all of the bleach being postadded. The various other constituents present will normally not exceed 2 percent and preferably will be held to 1 percent each, if present. Moisture contents of the spray dried beads will be from 1 to 18 percent, preferably from 3 to 15 percent and most often will be in the 5 to 12 percent range. This will also approximate the moisture contents of the final detergents made. After completion of the manufacture of the spray dried beads, accoring to a method which will be described subsequently, there is distributed over the surfaces thereof the nonionic detergent, which significantly improves washing action. Applications of liquid nonionic detergents to granular mixes of organic detergent and inorganic builder and filler salts have been effected in the past. However. the amounts of liquid nonionics employed usually had to be low, often under 1 percent or even under 0.5 percent, which small amounts could alleviate dusting problems and would not cause lumping or tackiness of the product but would also not greatly increase detergency. It has now been found, in accordancne with this invention, that from 2 to 20 percent, preferably 2 to 15 percent and most preferably about 5 to 10 or 12 percent higher linear alkoxy poly-lower alkoxy lower alkanol detergent may be oversprayed onto the base beads. Such detergent is preferably one in which the higher linear alkoxy is of 10 to 18 or 10 to 16 carbon atoms, most preferably of 12 to 15 carbon atoms and the poly-lower alkoxy lower alkanol is one in which the lower alkoxy and alkanols are of 2 to 3 carbon atoms each, with the total of carbon atoms in the poly-lower alkoxy lower alkanol, which is preferably polyethoxy ethanol, being 20 to 30. Preferably, the higher alkoxy is of 14 to 15 carbon atoms and the poly lower alkoxy lower alkanol is of about 22 carbon atoms. Such compounds are commercially available from Shell Chemical Company under the name, Neodol 45-11. Nonionic detergents similar to Neodol 45-11, made by Shell Chemical Company or other manufacturers, are also useful when they are of 10 to 18 or 13 to 16 carbon atoms in the higher alkanol and of 20 to 26 carbon atoms in the polyethoxy ethanol lll portions of the molecule. The nonionic overspray materials used will be liquid under the conditions of use and will preferably remain liquid or near-liquid after manufacture. Surprisingly enough, rather than such liquid state causing a plasticizing action and resulting in agglomeration or adherence of the particles to each other, it seem to promote penetration of the base beads and removal of the liquid from the surfaces thereof, causing the product to be free-flowing, and non-tacky.
With the application of the overspray nonionic detergent it may sometimes be desirable for other constituents of the final product to be added during the tumbling operation. For example, although in the drawing, perfume or other liquid additive is sprayed onto the tumbling particles through a nozzle separate from those utilized for the nonionic detergent, it may be blended in with the nonionic and sprayed through a single nozzle. Similarly, other liquid or soluble components or adjuvants may be sprayed. For example, amine anti-foam agents such as di-higher alkyl amine, e.g., dicocoyl amine, which may be present to the extent of 0.2 to 3 percent, usually about 1 or 2 percent, may be dissolved in the Neodol 45-11, together with the perfume. Likewise, foaming agents, bactericides, dyes and other coloring agents, solvents, etc., may be sprayed onto the base particles, either separately or together with other such materials. Mixtures of the nonionics, e.g., mixtures of Neodol 45-11, Alfonic 1618-65 and Plurafac B-26 may be employed.
To make no-foam detergents one will usually employ 2 percent soap 1 percent DCA (dicocoyl amine) or 2 percent of the amine, without any soap, in otherwise nonionic detergent formulas. Using 2 percent soap alone in such formulas makes a low foaming detergent. The use of DCA-Neodol 45-11 mixtures to apply them to the base detergent beads by overspraying gives a flowable non-tacky product superior to that obtained from separate oversprayings or from crutching the DCA and/or nonionic and spray drying.
In the tumbling apparatus or other suitable mixer in which the overspraying is effected, it will often be desirable for other constituents of the final product to be added. Usually, the most important of these is the antiredeposition agent and from 0.2, 0.3 or l to 5 percent of such an agent, preferably sodium carboxymethyl cellulose (CMC), hydroxypropyl methyl cellulose or polyvinyl alcohol, will often be blended in with the base detergent beads before overspraying. In some formulations, no organic anti-redeposition agent is needed but generally CMC will be a very useful additive. Stainremoving enzyme can be added at the same location as the CMC, usually to the extent of about 0.05 to l percent, and in the form of prills. The perfume content, generally from 0.1 to 1 percent of the product, may be added as previously described. If it is desired to further promote whitening or brightening of the surfaces of the particles a fluorescent dye or optical brightener, if soluble, may be applied in the overspray.
When considered to be advantageous, proportions of other constituents, normally as solid particles, may be incorporated in manner similar to that in which sodium carboxymethyl cellulose may be added. In such cases, corresponding amounts of such materials can be removed from the base formula. Such additions are especially desirable when the materials to be added in the tumbler are of substances which, in the spray dried or homogeneous detergent beads, inhibit penetration of the overspray into the beads, as do CMC and excess anionic detergent. For example, portions of sodium silicate and sodium sulfate may be added in the tumbler, rather than in the crutcher mix, to permit more ready processing of formulating containing larger amounts of these materials than would otherwise be desirable. On the other hand, sodium carbonate will usually not be post-added because it aids penetration of nonionic overspray into the interior of the base beads if it is in the bead formula. The post-added solid material in excess of 5 percent should preferably be granular (of particle size like that of the base bead). However, the CMC is usually added as a finely divided powder.
The oversprayed particulate detergent produced according to the foregoing formula and general procedure will be free flowing and does not tend to cake objectionably on storage. Thus, when at a density of about 0.3 to 0.6 grams/cu. cm., packed in cardboard detergent cartons, it pours easily despite storage at ordinary temperatures in humid atmospheres. Such a detergent box need usually only be tilted slightly to allow pouring of the contents as they are being measured for addition to a washing machine. For further insurance of excellent flow properties, however, it may sometimes be desirable to add from 0.2 to 3 percent of a very finely divided flow improving clay for such purposes, such as calcined aluminum silicate, sold as Satintone. Such additions will preferably be at a point near the outlet from the tumbling drum or will be effected near the end of the tumbling or mixing operation, after addition of the overspray liquid. This is done so that the clay will not be worked into the body of the detergent bead but will remain thinly spread out over the surfaces thereof to promote easy slip and free flow. For best effects, the clay should be sufficiently finely divided so as to pass substantially entirely (98 percent or more) through a 325 mesh sieve. Other ingredients, including salts and CMC, etc., can be added at either end of the mixer or intermediately but preferably are added upstream, with only Satintone being added at the downstream end.
Production of the homogeneous base may be by any suitable well-known method employed in the art. In spray drying operations, the general operation will be as outlined in the figures of the accompanying drawing. The crutcher mix will be heated to a temperature of about 60 to C. and will be sprayed through spray drying nozzles at a pressure of 200 to 2,000 lbs/sq. in. to globular droplets which will pass through drying gas, usually at a temperature of 150 to 300C, and will have their moisture content reduced to l5 percent or less. The dried particles resulting, which may be at 10 to 65C. but are usually at 27 to 43C., will largely be in the 6 to 200 or 6 to 140 mesh particle size range but may be screened to remove tailings. Preferably, the particles will be produced in the 8 to mesh range, US Standard Sieve Series.
When spray dried detergent particles are fresh and warm, having been spray dried within the half hour, often within 5 minutes or less and being at a temperature of from 27 to 43C., they are often soft so that upon addition of liquid materials they would be expected to agglomerate and become tacky. It is a feature of the present invention that, utilizing the homogeneous and preferably hollow globular detergent base beads with the particular nonionic detergent overspray described, overspraying is possible on fresh warm base particles without objectionable agglomeration. Thus,
special cooling and/or storage of the spray dried base particles are not neccessary and the efficiency of the manufacturing operation can be raised substantially. in fact, it is preferred to use fresh warm base particles, usually within 30 minutes to an hour after making and sometimes within five minutes or less. Rather than producing tacky or poorly flowing product as might have been expected, the fresh warm particles are usually even more sorptive than aged particles (several hours or a day old) and the product is better. The minor amount of agglomeration which may occur during practice of the present invention is not objectionable because the large particles readily break up in a screening operation. After screening, the particle sizes are in substantially the same range as originally produced and are still freely flowing beads or globules.
The spray dried base particles are charged to the tumbling machine, preferably a continuous tumbling drum, at one end thereof and, due to the inclination of the drum, usually from 2 to 15, often to they pass through it while continually tumbling so as to bring them in contact with beads and overspray material. Because the beads are substantially spherical and of rather large particle sizes, areas of contact between the particles are not great and strong aggregates are not formed. Yet, the liquid in the tumbler can be sorbed into the interiors of the particles. Preferably, the spherules will be in the 6 to 140 or 20 to 100 mesh range for best overspray results. Throughput times in the continuous tumbler or a batch tumbler, if that is employed, will. usually be from 1 to 20 minutes, preferably from 2 to minutes and most often around 4 to 6 minutes. The tumbling drum will rotate at about 2 to 30 revolutions per minute, usually 4 to 10 rpm. for best treatments.
Along with the base beads may be added finely divided sodium carboxymethyl cellulose or other antiredeposition agents of particle sizes that pass through a 200 mesh sieve, so that it is dry mixed with the detergent base beads, usually before application thereto of perfume or overspray nonionics. Other particulate solids, such as builders and fillers, may be added together with or at about the same locations in the drum as that at which the beads are added. Usually, the different particulate solid materials added are sufficiently mixed in the first 5 to 15 percent of the length of the tumbling drum and after such point liquids may be added. It is considered preferable to add the various solid components at the upstream end of the tumbler in a continuous operation, so that the liquid(s) are sprayed onto the dried mix. However, in variations of the process successful products may be made by later additions of particulate detergent components, in addition to additions of lubricant or Satintone, which is best added at the end of the drum or near the completion of tumbling.
Due to the rotation of the drum the particulate materials are lifted upwardly along the upwardly rising drum wall and fall downwardly before reaching the drum top, forming a continually surface-changing section or particle screen against which the liquid overspray may be directed. Thus, the overspray will normally be aimed at such surface at an angle inclined from the vertical and toward the surface. It will be apparent to one skilled in the art how this angle should be adjusted to obtain most effective covering of the particles with the liquid sprays. The most preferred direction will be that in which the sprayed droplets, whether of overspray material, perfume or other liquid, are directed onto the most rapidly moving portion of the base particles in the tumbler without contacting any quiescent sections of such particles and without touching tumbler walls or parts. Of course, the sprays should also avoid being directed at the inlets for the base beads, CMC or other particulate or powdered materials and usually should not be aimed at such incoming constituent streams.
The liquid droplets of sprays will normally be in the to 500 micron diameter range, preferably 50 to 250 microns. Such very fine particles tend to coalesce less and often a portion thereof will be carried as a fog through at least the early part of the tumbling apparatus, facilitating gradual contact with the base particles and allowing penetration of the liquid overspray without causing lumping or tackiness. The mass transfer of liquid overspray nonionic detergent through the detergent base bead is important for obtaining free flowing and non-tacky particles, and gradual contact of finely divided liquid with quickly moving or tumbling base particles allows the proper penetration of the liquid and contributes to satisfactory production of a free flowing product.
After tumbling for the desired time, the finished product is removed and without any special cooling being required, is packaged, following the procedure previously described, illustrated in the drawing. Such packing takes place within 30 minutes or less after removal of the product from the tumbling drum and when packed, the beads, which may still be warm, are so retentive of the overspray liquid (which may then still be in the liquid state, inside the base particles) that the particles will not badly stain an untreated cardboard carton at normal room temperatures. With waxed, resin-coated or otherwise treated cartons, results will be even better and the products will not cake, lump or become tacky on prolonged storage. Thus, the nonionic is sorbed by the beads sufficiently within the tumbling period to make the particles free flowing and not sticky. Their sorption coefficients are high, with from 2 to 20 percent of nonionic overspray being sorbed by a 6 to 200 mesh bead within 1 to 5 minutes. Flowability of the particles will be further improved if they have dusted onto the surfaces thereof /2 to l percent of a flow-inducing agent, such as Satintone or other suitable powdered constituent, toward the downstream end of the tumbler.
Within the proportions and conditions mentioned in this specification useful oversprayed detergent products are manufactured. A principal advantage of these products is in their desired content of nonionic detergent. Although it is difficult to spray dry any appreciable quantities of such compounds with other components of a detergent composition, by following the present methods a product is obtainable which is like a spray dried bead and yet, contains the desired amount of nonionic. Pluming, the production of bluish hazes over spray towers and the accompanying smoke and air pollution are obviated. Of course, for best processing and product results, the components, amounts thereof and conditions of treatment will be modified within the ranges given. For example, in compositions in which it is desired to include very large quantities of silicate, in which, although 30 percent is a usual upper limit, it might be wanted to extend to as much as 50 percent of the product in some instances, the very fact that silicate inhibits penetration by the nonionic detergent militates against more than 15 percent of the soluble silicate being included in the crutcher mix. Thus, the remainder, in such a case, will normally be separately produced in granular form and may be blended in with the detergent base or oversprayed particles in the early or late portions of the tumbling apparatus. Then too, if any CMC, NTA, sodium sulfate or anionic detergent, such as linear alkyl benzene sulfonate would be present in the base detergent in sufficiently large quantities, or a combination thereof would be present in such quantity, so that sorption of the nonionic would be inhibited, portions of these materials might Well be post-added. This is especially true of the CMC since only a small quantity of that material is tolerable in the crutcher mix without causing tackiness in the product after post spraying. Additionally, materials which aid penetration of the nonionic, such as sodium carbonate, might well be increased in crutcher mixes which contain inhibiting compounds, too. The amounts of lubricants or flowinducing powder such as Satintone should be increased if there is a danger that the product will not flow well, due to content of too much of materials which inhibit sorption of the nonionics. In a similar manner, the rule of reason with respect to formulation is applicable to the types of nonionic detergents that are employed. For example, where there are present penetrationinhibiting materials, it may well be preferable to utilize smaller quantities of the nonionics and the nonionics might be of more or less fluid types, such as those of lower or higher degrees of lower-alkoxylation. The more fluid compounds penetrate the detergent base beads better and the less fluid compounds do not migrate as readily to the surfaces of beads of higher nonionic contents.
In the specification the terms minor, major, substantial, substantially entirely and substantially all have been employed to describe various concentrations or proportions of materials. As so employed, minor means under 50 percent, major stands for more than 50 percent, substantial and substantially mean over 90 percent, and substantially entirely and substantially all in dicate over 98 percent.
Various advantages attending the practice of this invention are unexpected and are significant. Thus, the fact that the liquid nonionic detergent does not bleed from the detergent beads and make them tacky is surprising. That detergent particles which resemble spray dried detergents in their flowability are producible by this method would not have been predicted. Rather, it would have been expected that the beads would agglomerate, lose their spherical outlines, increase in particle size and be of diminished flow rates. Strangely enough, in most cases the bulk density of the product does not change during treatment, nor does its particle size distribution vary much from that of the starting material. It might well have been anticipated that the addition of liquid post-spray would cause a significant increase in bulk density of the particles. That the process of overspraying should be so efficient and so quickly effected is surprising, as is a noted lack of criticality with respect to continuing the tumbling for substantial periods of time, up to 30 minutes, after completion of normal sorption of the overspray. It would normally be expected that such additional tumbling would be detrimental to the detergent bead but such is found not to be the case.
Other significant and surprising effects attending the present invention include the use of hydrous silicate or other detergent composition components which would normally tend to limit sorption of nonionics on the detergent base particles, which use is effected in such a manner as to limit their abilities to dissolve in the crutcher mix before spray drying. Since it appears to be soluble forms of such components which inhibit sorption of the nonionic detergent, by adding them last, temporarily coating them with protective agents, agitating for only a short period of time, utilizing comparatively large particle sizes, etc., the solubilities of such crutcher components are minimized and a product is made which may usefully sorb nonionic detergents sprayed thereon. Of course, the coating materials, particle sizes, etc., are chosen so that in final detergent use the added components will dissolve and exert useful washing or adjuvant effects. The sorption of nonionic detergent on the carbonate-containing beads appears to be a combination of absorption and adsorption. Enough of the liquid penetrates to the interior of the bead to prevent it from being unduly wet and the nonionic on the surface appears to be held there so that it does not cause particles to stick together. Whatever the mechanism of sorption, the significant result obtained is a free-flowing product which may be high in nonionic detergent content.
Although the nonionic content may range from 2 to 20 percent, usually, if the nonionic detergent is the only detergent present and is mostly or entirely in the overspray, the limit thereon will be about 15 percent. It has been found that 16 percent can be incorporated in a freely flowable product if the detergent beads are fresh, that is at a temperature of 27to 43C. and less than 2 hours old, preferably less than 30 minutes and most preferably, less than 5 minutes old. Such beads sorb the nonionic better, whereas if they are allowed to stand for a day, addition of lubricant (Satintone) is desirable to maintain the free flowing nature of the product. By the present method, spray dried and oversprayed products high in nonionic detergent content may be made and products in which the active organic detergent is a mixture of anionic and nonionic, totaling about 14 percent and about equally divided between the two types of organic detergents, may be made, although such formulas cannot be spray dried economically from crutcher mixes.
A surprising aspect of the present invention is in the free flowing nature of the recently oversprayed detergent particles. Despite their contents of silicate, sulfate. anionic detergent and sometimes, anti-redeposition gums, all of which act to slow down sorption, because of the presence of sodium carbonate and the adherence to formula restrictions given. quick sorption is obtainable. Thus, product may be packed immediately after removal from the overspraying apparatus whereas, for formulas outside the described ranges which also contain sorption-inhibiting agents. a curing period of about a day is required. A 24 hour holdup of all the produced detergent requires huge storage facilities plus transporting equipment, all of which are unnecessary when the present invention is followed. For compositions outside the present invention which are not satisfactorily aged to suitable for passing through filling equipment, lazy movements thereof often cause only partial fills of cartons and sometimes result in jamming of the filling equipment. Another important advantage noted for the products of this invention is that the fluorescent dye or optical brightener incorporated in the crutcher mix, when the detergent particles containing it are oversprayed, whitens the product much more than the same amount of dye in a product which has not been oversprayed. It appears that the nonionic overspray material encourages migration of the fluorescent dye to the surfaces of the beads, increasing their concentrations at the bead exteriors. Such a mechanism can also be useful in maintaining concentrations of perfumes and similar adjuvant materials higher at the outside of the detergent particles than in the interior, giving it a greater appeal to the consumer or allowing a saving in the quantity of perfume employed. It has also been theorized that the nonionic detergent may also improve the transparency or translucency of the surface of the particles, thereby better enabling the optical brighteners to whiten the product.
In addition to the mentioned unexpectedly beneficial results, the present processes and formulations allow the making of excellent, free flowing detergent products by efficient and practicable means, utilizing available equipment and actually improving its capacity.
The following examples illustrate the invention but should not be considered as limiting it. Unless otherwise mentioned, all temperatures are in F. and all part are by weight.
C averaging about C 87.5% active ingredient, the balance being sodium sulfate and 2.571 unreacted oil (alkyl benzene).
The listed components of the 65 percent solids crutcher mix for making the detergent base are sequentially added to a crutcher and are mixed therein for about minutes, with the final temperature of the mix in the heated crutcher becoming about 185F. The mix is then pumped to a spray drying tower of the countercurrent type, spray dried to base beads and the beads are tumbled while overspraying materials are applied to them, after which they are packaged. The method followed is in accordance with the drawing. However, it should be understood that operations and equipment not essential for the practice and understanding of the invention have been omitted from the drawing and from this description in the interest of simplicity of presentation.
The crutcher mix is pumped to the spray tower by a positive pressure pump which produces about 800 pounds gauge pressure at a manifold before the spray nozzle. A single No. 2-15 Whirljet spray nozzle is used to spray the crutcher mix into the top of the 60 ft. high, 8 ft. diameter tower. The inlet air temperature to the tower is 450500F. and the outlet temperature is about 400F. The slurry enters the spray nozzle at about 180F. Residence time of the droplets and particles in the tower is about 1 to 4 minutes. The product is withdrawn at the bottom of the tower and is air lifted to a bin from which it is dispensable to a mixing drum or twin shell blender, in which the overspraying operation is effected. Extensive experimentation has shown that the actions of batch and continuous tumbling drums and twin shell blenders are substantially equivalent, with respect to the characteristics of the products produced. Accordingly, in commercial operations the continuous inclined drum tumbler will usually be employed because it produces a satisfactory product and often has a much higher throughput rate than corresponding batch tumblers or blenders.
The spray dried detergent base beads, of particle sizes in the 6 or 8 to 140 or 200 mesh range, a substantial proportion of which is in the 6 to 100 range and the major proportion of which is in the 6 to mesh range, have a moisture content of about 10 percent, upon being charged to the tumbling apparatus. They are of a density of about 30 lbs. per cubic foot and a temperature of about 80F. to 120F.., when charged.
To a continuous tumbling drum like that illustrated in the drawing are added, within a half hour of manufacture and in many instances, within 5 minutes, about 90.5 parts of the base bead, including about 9 to 10 percent moisture, 2 percent of powdered CMC and 7.5 percent of Neodol 45-11. At the temperature of addition, about F, the Neodol 45-11 has a viscosity of about 68 centipoises. No perfume, enzymes or Satintone or other flow-improving agent is utilized in this run but such may be added at the points previously described in the specification, if desired. The CMC em ployed is finely powdered, passing through a mesh sieve and with substantially all passing a 200 mesh sieve. It is added in the beginning portion of the tumbling drum by a metering device and is substantially mixed with the detergent base: beads in the first 5 to 15 percent of the length of the tumbler. The tumbler is operated at about 25 rpm. and blending takes about 4 to 8 minutes, with the initial 30 seconds being allowed for blending the CMC with the base beads. The Neodol 45-11 is sprayed into the mixing drum in spherical particles approximately 50 to 100 microns in diameter, which are directed against a wall of falling detergent beads. The spray is made by using a Spray Systems Inc. round spray cone atomization nozzle at an air pressure of about 40 lbs/sq. in. gauge. After completion of mixing the beads are withdrawn and are immediately packaged (within a minute) in carlboard cartons, which are sealed and sent to storage.
The product made is an excellent household laundry detergent for use in automatic washing machines. It has a flow rate of between 60 and 70 percent, which is good. (See out application entitled MANUFACTURE OF FREE FLOWING PARTICULATE DETERGENT CONTAINING NONIONIC SURFACE ACTIVE COMPOUND, filed Mar. 15, 1971, which is incorporated by reference herein, for additional information on flow rate tests and other procedures, ingredients, processes, etc.). The final product is also found to be non-tacky and does not pack or lump objectionably. Its bulk density is about the same as that of the starting detergent base beads.
The above overspraying method utilizes a tumbling drum like that shown in the drawing but when a batch operation is desired to be effected, the same equipment may be used, 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 about and the more central addition of materials and overspray thereon, to obtain equally good results. Similarly, continuous or batch twin-shell blenders, with and without breaker bars, and equipped with internal sprays, may be used to obtain such results. However, for speediness and ease of manufacture and control of product quality, the continuous drum blender illustrated is preferred.
By the method of this example there is produced a built detergent composition containing approximately equal amounts of anionic and nonionic detergent and with the total content thereof at about 14 percent. Such a formula cannot be produced by spray drying only, without waste of nonionic and violation of antipollution codes, due to the pluming of the nonionic from the spray tower. Yet, by the present method, a free flowing, high quality product results with little extra processing and without producing the objectionable plume.
In formulas of this type, when the proportion of soda ash is increased, replacing the sulfate, the products made are not as freely flowing as those wherein the sulfate is present with the soda ash. This result for anionicnonionic detergents is different from that noted for allnonionic products. In both cases the presence of sodium carbonate is very helpful in producing a free flowing and non-tacky product.
An important advantage noted is that the overspraying of the nonionic detergent results in a whiter or brighter product, apparently due to an effect of the overspraying on the content of fluorescent dyes or optical brighteners in the base beads, whereby they are attracted to near the beads surfaces.
Instead of Neodol 45-11 in the overspray, other Neodols within the description given may be used, either in replacement of the Neodol 45-11 or together with it, to obtain similar results. In a like manner, replacement may be with Plurafac B-26 or Alfonic 1618-65 and a good product will be obtained. A small proportion, preferably no more than 0.2 percent of CMC or other antiredeposition agent (most preferably, none) may be present in the crutcher without interfering with the overspraying operation. Builders and fillers may be employed in place of those shown. Thus, percent of borax may be used in place of some of the tripolyphosphate and 5 percent salt may replace some of the sulfate. The silicate may be replaced in whole or in part by other metasilicates of Na O:SiO ratio of 1:2 or 112.6 and hydrosilicates may be employed as such a replacement to the extent of about 3.5 percent in this formula. Other anionic detergents, including sodium lauryl sulfate and sodium coco-tallow soaps, and other nonionics, including nonyl phenoxy polyoxy ethanols (Igepal CA-630) may replace a part of the respective anionic and nonionic detergents, to the extent of about 3 percent, without changing the characteristics of the product greatly. In a similar manner, the proportions of the various constituents may be altered, as may be the processing temperatures, times, etc., within the scopes described in the specification. When the proportions are changed about i percent, the product resulting has properties essentially the same as those of that described.
Particle size of the detergent base beads to be sprayed has a bearing on flowability of the oversprayed detergent. Thus, when particle sizes are in the 60 to 200 mesh range flowability will be descreased, compared to a similar product in the 6 to 60 mesh range. However, even with the smaller particles, the products of the present formulas and treatments will be superior to those not containing the carbonate and silicate or which are manufactured by ordinary powder mixing methods. Also, although when ordinary detergent compositions, containing no carbonate, are post-sprayed with nonionic, it may be possible to add as much as 5 percent of nonionic to the product, providing that no CMC at all is present in the crutcher, the silicate content is kept low and the product sprayed is a spray dried product of large bead size, even in such situations products made according to the invention are superior in flowability when of the same bead sizes.
EXAMPLE 2 Parts by weight Water 130.0 Fluorescent brightener (Stilbene No. 4) 2.0 Fluorescent brightener (ALF) 0.5 Antioxidant 0.3 Sodium carbonate, anhydrous 310.0 Sodium silicate (Na O:SiO 1:2.32), 1 16.0
43.2% solids aqueous solution Water, fluorescent brighteners, antioxidant, sodium carbonate and sodium silicate are added sequentially to a heated crutcher and the procedure described in Example 1 is followed. In the tumbling apparatus there is mixed with spray dried base detergent beads, which are of hollow, substantially globular form and analyze about 10 percent moisture, 3 parts of sodium carboxyrnethyl cellulose per 82 parts of beads and there is then sprayed onto the surfaces of the tumbling beads 15 parts higher alkoxy polyethoxy ethanol (Neodol 45-11 The product taken off, a low sudsing built nonionic detergent, containing l5 percent of the nonionic detergent material, is in flowable form and is not tacky. It does not lump in the carton on ordinary storage at the usual room temperatures. However, when the temperature is raised to about 120F. for any period of time, some staining of the nonionic detergent onto container walls may be noted. When products are to be stored at such temperatures, barrier linings will usually be employed in the cardboard boxes. When larger quantities of nonionic overspray material, within the range of this invention, are employed, it may be desirable to utilize a flow-aiding agent, such as Satintone, or other suitable powdered clay product, to improve flowability and diminish any minor tendency to tackiness.
In additional experiments it has been noted, with respect to the essentially inorganic spray dried base bead, that best sorption of nonionic is obtained when the moisture content of the bead is from 0.5 to 5 percent and the particle sizes are in the 6 to mesh sieve size range.
EXAMPLE 3 Following the procedure described in Example 1, there is produced an essentially inorganic spray dried detergentbuilder composition comprising 15 parts sodium carbonate, anhydrous; 33 parts sodium tripolyphosphate; 18 parts sodium sulfate, anhydrous; parts of sodium metasilicate of a Na O:SiO ratio of about 112.3; and 10 parts of water. To this, in the described tumbling drum are added by overspraying 10 parts of higher alkoxy polyethoxy ethanol wherein the higher alkoxy is mixed C and C and the ethoxy ethanol content is such that it contains about 22 carbon atoms, and 2 parts of dicocoyl amine. The dicocoyl amine (Armeen 2C, made by Armour Chemical Company), is first melted and blended with the liquid nonionic higher alkoxy polyethoxy ethanol, after which the mixture is sprayed onto the detergent base beads, which are of particle sizes that pass through an 8 mesh U.S. Standard Sieve Series sieve and rest on a 140 mesh sieve.
The dicocoyl amine is useful in these compositions as an anti-foaming agent and prevents any foaming at all of the product. Instead of utilizing 2 percent, in similar experiments 1 percent has been incorporated with the nonionic detergent and 2 percent of sodium cocotallow soap (85:15) replaces 2 percent of the sodium sulfate in the spray dried beads. When the dicocoyl amine or other higher alkyl amine anti-foam agent is added in the crutcher, it is usually destroyed or lost during the spray drying process. When it is added separately in the tumbling drum, it causes tackiness and sticking of the product. However, by following the method of this example, a good free flowing, nontacky, non-foaming product is obtained.
In changes of the formula and process, the proportions of nonionic are varied from 5 to 15 percent, with the obtaining of similar improved results. The proportion of dicocoyl or other dialkyl amine may be varied over the range of 0.5 to 4 percent but usually 1 to 2 percent will be used. Similar changes in the contents of sodium carbonate, sodium tripolyphosphate and sodium sulfate may be made within the ranges described in the specification, and the moisture content may be adjusted in like manner. With respect to sodium silicate content, it will normally be undesirable to increase this above 15 percent, unless it is post-added, or hydrous silicate or some other form of unreactive silicate, which does not prevent sorption of the nonionic, is employed in the crutcher mix, such employment being in a manner to prevent its dissolving before intended final use. When the hydrous or other metasilicate is added to the tumbling drum it yields best results and most free-flowing product, with a minimum of tailings, especially when the silicate granules employed are in the 8 to 140 mesh range.
To improve the anti-redeposition properties of the product, about 0.5 to 5 parts of sodium carboxymethyl cellulose are added, sometimes with from 5 to 10 parts of granular hydrous silicate, in the tumbling drum.
Although good results are obtainable when the nonionic detergent-DCA blend is applied at slightly elevated temperataures (it is desirably made by first heating to 60 to 70C. and blending the components), in many applications, such as that described herein it will be more desirable to heat this mix to a temperature of 50-70C. before spraying.
The density of the product made is about 0.7, a little higher than the preferred 0.3 to 0.6 g./cc. range but this can be lowered by utilizing different spray nozzles and larger particle size beads. The density is only very slightly greater than that of the base beads employed.
The final product has an excellent flow rate, being 76 percent by the flow test employed.
EXAMPLE 4 In a manner similar to that followed in Example 3, a base bead comprising 2 parts of sodium coco-tallow soap (approx. :15); 50 parts soda ash; 10 parts sodium metasilicate (1:2.3 Na O:SiO ratio); 10 parts of water and 15 parts hydrous sodium silicate, added last to the crutcher mix, just before spray drying, is prepared by crutching and spray drying to hollow globular beads of the size range previously described in Example 3. Then, 0.5 percent of sodium carboxymethyl cellulose is admixed with the beads in the tumbling drum and a mixture of 12 parts of Neodol 45-11 and 1 part of Armeen 2C is sprayed onto the tumbling beads. The beads are at approximately room temperature and the liquid being sprayed is initially at a temperature of about 65C. At the end of the tumbling drum is added 2 percent of Satintone flow-improving agent. Although the product is not as free flowing as many of the formulations containing lesser proportions of silicate, it does flow fast enough to be fillable into cartons by automatic filling equipment, without undue bridging or blocking of passageways, which would otherwise cause holdups in the filling line. When a lesser amount of flow improving additive is used the flow test results are poorer, as would be expected.
Contrary to the results obtained in Example 3, the densities of the products of this experiment are in the 0.2-0.3 g./cc. range and the flow rates are less than those of the spray dried beads charged to the tumbling drum. When the blending times are varied over the range of 3 to 10 minutes the physical properties of the product are not significantly altered. Similar results are obtainable when larger quantities of sodium carboxymethyl cellulose are used, from 0.6 to 3 percent, and when a portion of the soda ash is replaced by 15 parts of sodium sulfate and the hydrous silicate is replaced by sodium tripolyphosphate. Also, the addition of 0.1 to 2 percent of fluorescent brightener in the crutcher mix (preferably replacing some of the silicate) and the spraying on of 0.1 to 1 percent of perfume in the tumbling drum do not change the properties of the product. It is noted that the post treatment of the spray dried beads improves the whiteness thereof, apparently due to the fluorescent dye being aided in migrating to the beads surfaces.
Although additional experimentation is being conducted to find better ways of adding the hydrous silicate in the crutcher so that the proportion thereof dissolving may be diminished, a preferred method at the present is to add the hydrous silicate in the tumbling drum as granules of approximately the same particle size distribution as the spray dried beads. It has been found that the less chance there is for dissolving of the hydrated silicate, the more free flowing the product. Certainly in post-adding the silicate to the tumbling drum the dissolving is minimized.
When instead of 10 parts of hydrous silicate being 1 added in the crutcher, 30 parts thereof are added in the l tumbling drum, with the porportion of soda ash being thereof the flow rate is increased to 65 percent, which is highly acceptable, and the density is still about 0.35.
EXAMPLE 5 b-COO The above composition is sprayed from a 60 percent solids aqueous crutcher mix in a spray tower like that described in Example 1 and in accordance with the method mentioned therein. While still fresh, at a temperature of about 110F., the detergent composition base beads, of hollow globular form and of particle sizes in the 6 to 140 mesh range, are fed by the illustrated apparatus, a weigh belt feeder, to an 18 ft. long rotary drum or cylinder, having a diameter of about 2 /2 ft. 0.85 Part of sodium carboxymethyl cellulose is also fed to the tumbling drum, through the same chute as the detergent base beads, with the feed of base beads varying from 94 to 87 parts. 0.15 Part of detergent perfume is blended with 7 parts of Neodol 45-11 and from to 12 parts of this mixture, heated to 140F., is sprayed into the tumbling drum onto the detergent beads, as illustrated in FIG. 3, except for no separate perfume spraying. The ratios of base CMC to Neodol 45-11 perfume are varied from 95:5 to 88:12.
Tumbling in the drum, which rotates at about 16 rpm. takes place at about room temperature, approximately 80F, with about 130 lbs. of mateial in the drum at any time, a residence time of about 7 minutes and a throughput of about 16.5 pounds per foot and hammers are employed to keep material from adhering to the side thereof.
The products obtained are of a density of 0.5 to 0.6 g./cc., flow well and are not tacky. No Satintone or other lubricants are needed to promote flow. In the detergent beads manufactured, there are present 7 percent of anionic detergent and from 7 to 14 percent of the nonionic detergent.
The product produced is brighter appearing than the base beads, despite the fact that there is a lower content of fluorescent brighteners in the post-sprayed detergent. The particle sizes of the detergent are about the same as those of the base beads charged to the tumbling drum.
When the amount of sodium tripolyphosphate is reduced to 23 percent and the soda ash is increased to 20 percent, an even better flowing detergent is made. Similarly, when the Neodol 45-11 is omitted from the crutcher mix and is replaced by sodium sulfate, better sorption of the nonionic overspray results. In some embodiments of the invention, fluorescent brighteners or portions of the fluorescent brightener charge are mixed in with the overspraying materials to produce brighter detergent beads. When part of the tripolyphosphate, 6g. percent thereof, is post-added, together with an additional proportion, e.g., 10 percent of the sodium metasilicatc, perferably as hydrous sodium silicate.
leaving the base beads providing 23 percent of the sodium tripolyphosphate and 12 percent of the anhydrous sodium sulfate, good detergent products which are free flowing and non-tacky also result.
EXAMPLE 6 A series of detergent compositions is made substantially in accordance with the method described in Example l and the flow rates and densities of the products made are recorded. The products include 10 percent of sodium silicate (Na O:SiO 1:2.3 7 percent of linear higher alkyl benzene sulfonate, sodium salt, and 7 percent of higher alkyloxy polyethoxy ethanol (Neodol 45-11). Variations in the base bead composition and in the final product formulas are explored to determine their effects on flowability of the detergent beads produced. With 66 percent (all percentages are on a final product basis) of soda ash and 0.5 percent of sodium carboxymethyl cellulose in the crutcher with the silicate and linear tridecyl benzene sulfonate, flowability is poor after post-spraying onto the base beads of the 7 percent of Neodol 45-11. However, when the sodium carboxymethyl cellulose is omitted from the formulation and the soda ash content is increased to 67 percent, the flow is 62 percent, which is highly acceptable. Densities of the products are 0.35 and 0.45, respectively. When the crutcher mix comprises 66 percent sodium sulfate, 10 percent silicate, 7 percent of the anionic detergent and 0.5 percent of CMC, the flowability is 0, as is also the case when the CMC is omitted. With 33 percent of tripolyphosphate, 34 percent of sodium sulfate, 10 percent of sodium silicate and 7 percent anionic detergent, flowability is 0 but when the sulfate is replaced by soda ash, flowability increases to 68 percent. For a 33 percent TSPP, 10 percent silicate and 7 percent anionic detergent bead, containing from 8.5 to 25 percent of sodium sulfate and from 25 to 8.5 percent soda ash, excellent fiows are obtained. Such results also obtain when the TSPP is replaced with TPP. Similarly, when l or 2 percent of Neodol 45-11 and/or 1 or 2 percent of soap is present in such formulations, good flows are obtained except in the simultaneous presence of soap and the absence of Neodol 45-11 and sodium sulfate from the base bead. When 20 percent of sodium citrate is added to such formulations, in replacement of some of the TPP, so that TPP content is dropped to 15 percent, flow is good, providing that l or 2 percent of Satintone is present. When an percent soda ash, 15 percent silicate and 5 percent moisture bead is made, later blended with l percent CMC and oversprayed with 10 percent Neodol, a flowable detergent results.
A wide variety of other experiments is conducted, varying the proportions of the constituents within the ranges described in this specification, and good detergents which are free flowing, non-tacky and stable are obtained. Such is also the case when processing conditions are changed within the ranges given with respect to temperatures, times, speeds, type of tumbling employed, etc. The conditions to employ will be clear to one of skill in the art, following the specification. No extensive experimentation to determine formulas and processes will be necessary.
The invention has been described with respect to working examples and illustrations thereof but is not to be considered as being limited thereto. since equivalents and substitutes may be employed within the inventive concepts.
What is claimed is:
1. A method of producing a particulate detergent composition which comprises making inorganic salt containing base particles comprising, on a detergent composition weight basis, at least percent of sodium carbonate, sodium bicarbonate or sodium sesquicarbonate, at least 5 percent and less than 30 percent of sodium silicate, having Na O:SiO ratio of 1:1.6 to 1:3.4, less than 15 percent of soluble higher alkyl benzene sulfonate detergent, less than 4 percent of nonionic detergent and less than 0.5 percent of sodium carboxymethyl cellulose, with the components of the base particles being such that the subsequently mentioned nonionic detergent is readily sorbed thereby, and distributing over the surfaces of the particles, while they are in motion, from 2 to 20 percent by weight of the detergent composition of a higher alkoxy poly-lower alkoxy lower alkanol containing nonionic detergent wherein said higher alkoxy contains from to 18 carbon atoms, said lower alkoxy and lower alkanol contains from 2 to 3 carbon atoms, the total number of carbon atoms in said poly lower alkoxy lower alkanol being from 20 to 30.
2. A method of producing a particulate detergent composition which comprises spraying onto the sur faces of detergent particles while they are in motion, said detergent comprising on a detergent composition weight basis, at least 5 percent of sodium carbonate, sodium bicarbonate or sodium sesquicarbonate, at least 5 percent and less than 30 percent of sodium silicate, having Na O:SiO ratio of 121.6 to 1:3.4, less than percent of soluble higher alkyl benzene sulfonate detergent, less than 4 percent of nonionic detergent and less than 0.5 percent of sodium carboxymethyl cellulose, with the components of the base particles being such that the subsequently mentioned nonionic detergent is readily sorbed thereby, from 2 to percent by weight of the detergent composition of higher alkoxy polylower alkoxy lower alkanol containing nonionic detergent, said higher alkoxy containing from 10 to 18 carbon atoms, said lower alkoxy and lower alkanol containing from 2 to 3 carbon atoms, the total number of carbon atoms in the poly lower alkoxy lower alkanol being from 2 to 30.
3. A method according to claim 1 wherein the detergent composition particles comprise from 5 to 12 percent of sodium linear higher alkyl benzene sulfonate wherein the higher alkyl is of 12 to 15 carbon atoms, 0 to 3 percent of higher alkoxy poly-lower alkoxy lower alkanol nonionic detergent compound wherein the higher alkoxy is linear alkoxy of 10 to 18 carbon atoms and the poly-lower alkoxy lower alkanol is polyethoxy ethanol of 20 to 26 carbon atoms, 5 to 75 percent sodium carbonate, 15 to 50 percnt pentasodium tripolyphosphate, 5 to 30 percent of sodium silicate of Na Oz- SiO ratio of from 1:2 to 1:3, of which no more than 15 percent is dissolved in the aqueous mix that is spray dried, and from 2 to 15 percent moisture, all of which materials are in the base particles, sodium silicate, pentasodium tripolyphosphate and anti-redeposition agent selected from the group consisting of carboxy methyl cellulose, hydroxypropyl methyl cellulose, polyvinyl pyrrolidone and polyvinyl alcohol are admixed with the base particles, and the higher alkoxy poly-lower alkoxy lower alkanol nonionic detergent applied to the base particles and particles mixed with them is one in which the higher alkoxy is linear alkoxy of 10 to 18 carbon atoms and the poly-lower alkoxy lower alkanol is polyethoxy ethanol of 20 to 26 carbon atoms, and is from 2 to 15 percent of the detergent composition.
4. A method according to claim 3 wherein the detergent composition particles comprise from 5 to 10 percent of the sodium linear higher alkyl benzenesulfonate, 8 to 13 percent of the :sodium silicate, 25 to 50 percent of pentasodium tripolyphosphate, 5 to 10 percent moisture, 12 to 40 percent sodium sulfate, 2 to 40 percent sodium carbonate, the proportion of such carbonate with respect to sodium sulfate being at least 1:3, all of which preceding components are in the spray dried base particles, from 5 to 10 percent of higher linear alkoxy poly-lower alkoxy lower alkanol nonionic detergent, applied to the base particles as a spray and from 0.5 to 5 percent carboxy methyl cellulose, applied as a finely divided powder to the tumbling base particles in the same tumbler in which the nonionic detergent spray is applied thereto.
5. A method according to claim 3 wherein the detergent composition particles comprise from 5 to 8 percent of sodium linear tridecyl benzene sulfonate and 5 to 8 percent of higher alkoxy polyethoxy ethanol wherein the higher alkoxy is of 14 to 15 carbon atoms and the polyethoxy ethanol is of 22 carbon atoms.
6. A method according to claim 4 wherein from 0.1 to 2 percent of a synthetic organic fluorescent brightening compound is present in the base beads, causing brightening of the surfaces of the detergent particles when contacted with the sprayed nonionic detergent, and from 0.1 to 1 percent of perfume is sprayed onto the beads in the tumbler.
7. A method according to claim 1 wherein the base particles are made by spray drying an aqueous mix comprising sodium carbonate, sodium silicate, soluble higher alkyl benzene sulfonate detergent and water and the higher alkoxy poly-lower alkoxy lower alkanol is sprayed onto the surfaces of the spray dried particles in fine liquid droplet form while the base particles are in tumbling motion.
8. A method according to claim 7 wherein the base particles to which nonionic detergent is applied are substantially hollow globules which pass through a 6 mesh US. Standard Sieve Series sieve and remain on a 200 mesh US. Standard Sieve Series sieve and are at a temperature from 10 to 65C. when the liquid spray, of particle size from 50 to 500 microns, at a temperature of 10 to 65C., is applied thereto, which application takes place within 30 minutes after removal of the spray dried particles from the spray dryer.
9. A method according to claim 8 wherein the detergent composition particles comprise from 5 to 12 percent of sodium linear higher alkyl benzene sulfonate wherein the higher alkyl is of 12 to 15 carbon atoms, 0 to 3 percent of higher alkoxy poly-lower alkoxy lower alkanol nonionic detergent compound wherein the higher alkoxy is linear alkoxy of 10 to 18 carbon atoms and the poly-lower alkoxy lower alkanol is polyethoxy ethanol of 20 to 26 carbon atoms, 5 to 83 percent sodium carbonate, 5 to 25 percent sodium silicate of Na O:SiO ratio of from 1:2 to 1:3 and from 2 to 15 percent moisture, all of which are in the base particles, and the higher alkoxy poly-lower alkoxy lower alkanol nonionic detergent applied to the base particles is one in which the higher alkoxy is linear alkoxy of 10 to 18 carbon atoms and the poly-lower alkoxy lower alkanol is polyethoxy ethanol of 20 to 26 carbon atoms and comprises from 2 to 15 percent of the detergent composition.
10. A method according to claim 9 wherein there is present in the spray dried base particles, on a detergent composition basis, 15 to 40 percent sodium sulfate, with the proportion of sodium carbonate to sodium sulfate being at least 1:3, percent of higher alkoxy polylower alkoxy lower alkanol nonionic detergent and 0 percent sodium carboxymethyl cellulose, the higher alkoxy poly-lower alkoxy lower alkanol nonionic detergent applied to the base particles is from to 12 percent of the detergent composition, with the total of sodium linear higher alkyl benzene sulfonate and higher alkoxy poly-lower alkoxy lower alkanol nonionic detergent being from 8 to 16 percent, and from 0.5 to 5 percent of sodium carboxymethyl cellullose is added as a finely divided powder or in granular form to the tumbling base particles in the same tumbler in which the nonionic detergent spray is applied thereto.
11. A method according to claim 8 wherein from 3 to 15 percent of sodium silicate is maintained undissolved in a crutcher mix, from which the base particles are spray dried, by adding thereto, as one of the last components of the crutcher mix, a hydrous sodium silicate in particulate form of relatively large particle size, compared to the other particulate materials added to the crutcher mix, maintaining the temperature of the crutcher mix sufficiently low so as to allow the hydrous sodium silicate to remain substantially undissolved, mixing slowly after the addition of hydrous sodium silicate, and spray drying the crutcher mix within 10 minutes after addition of the hydrous sodium silicate.
12. A method according to claim 8 wherein there is spray dried in the base bead from 5 to 20 percent, on a detergent composition basis, of sodium citrate, as a builder.