CA1128829A - Phosphate-free high bulk density particulate heavy duty laundry detergent - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A phosphate-free, free flowing, particulate heavy duty laundry detergent of high bulk density, 0.6 g/ml or more, includes particles of mixed alkali metal bicarbonate and alkali metal carbonate, at least some of which are in the form of Wegscheider's salt, containing and coated with non-ionic detergent.

Description

This invention relates to an improved phosphate-free, free flowing, particulate heavy duty laundry detergent.
More particularly, it relates to such products comprising sodium bicarbonate, sodium carbonate and normally liquid or pasty nonionic detergent.
Ileavy duty powdered laundry detergents based on synthetic organic detergents and builder salts are well known and have been employed extensively as household and commercial detergents for washing soiled clothing and other such items.
Although sodium tripolyphosphate is among the best of a variety of builder salts employed in such heavy duty detergents, phosphate contents of detergent compositions have been limited by law and regulations in view of evidence which has been interpreted to indicate that phosphates contribute to ~

-- 1 -- , ~,...

~2~

eutrophication of inland waters when discharged into such waters either directly or indirectly. Accordingly, substitute builders have been sought. Sodium carbonate is a known builder for synthetic organic detergents and sodium bicarbonate has also been employed in detergent compositions. Nonionic detergents have recently found increased favor as principal organic detergents in laundry products whereas previously they were usually employed, if at all, as supplements for anionic organic detergents.
It is known that high bulk density detergents can be made but these very often have been objectionably fine powders which can "smoke", causing sneezing and eye irritation, when they are poured out of a box or other container during use.
Attempts have been made to produce free flowing and dust-free particulate detergent compositions of increased concentrations of active ingredients and increased bulk densities so that comparatively small quantities thereof could be employed and detergent boxes could be diminished in size. Although a product which includes nonionic detergent, sodium bicarbonate, soaium carbonate and zeolite builder is an excellent detergent the present compositions, which do not require the presence of the zeolite, are also satisfactory phosphate-free, non-caking r C

and freely flowable particulate detergents of comparatively high bulk density. In accordance with the present invention a phosphate-free, free flowing, particulate heavy duty laundry detergent of bulk density of at least about 0.6 g./ml., moisture content below 10% and par-ticle sizes in the range of 4 to 100 mesh comprises nucleus particles of mixed alkali metal bicarbonate and alkali metal carbonate in which the proportion of bicarbonate to carbonate is in the range of 1:0.4 to 1:0.8, containing a normally liquid or pasty nonionic detergent in such quantity that the percentage of such detergent in the product is from 15 to 22% and the proportion of nonionic detergent to the total of alkali metal bicarbonate and alkali metal carbonate is in the range of 1:2.5 to 1:4, and hydrous sodium silicate.
Preferably, the mixture of alkali metal bicarbonate and alkali metal carbonate is a mixture of sodium bicarbonate and sodium carbonate containing at least 10% of Wegscheider's salt, the nonionic detergent is a higher fatty alcohol-polyethylene oxide condensation product wherein the higher fatty alcohol is of 10 to 18 carbon atoms and the polyethylene oxide is of 5 to 12 mols of ethylene oxide per mol of higher fatty alcohol, and the hydrous sodium silicate is of Na2O:SiO2 ratio in the range of 1:1.8 to 1O3.2 and is hydrated by about 10 to 25% moisture.
The mixture of alkali metal carbonate and alkali metal bicarbonate is one wherein both types of compounds are present in the same individual beads or particles. For the purpose of this invention such particles should desirably have sizes within the 4 to 100 mesh range, preferably being 10 to 60 mesh and most preferably about 20 to 40 mesh (the word "mesh" is used interchangeably with "No."). Larger particles may be ,~
t used providing that the resulting final product size is in the desired range. In some such cases efforts will be made to pre-vent any agglomeration or appreciable size growth taking place during absorption of nonionic detergent so as to avcid such particles becoming too large. When sizes smaller than those in the desirable range indicated are used there is sometimes pro-duced an unacceptable pasty product, rather than individual free flowing beads.
The alkali metal (sodium or potassium being preferred) carbonates and bicarbonates, most preferably as the sodium salts, will be essentially anhydrous in preferred embodiments of the invention but partia]ly hydrated builder salts of this type may be tolerated. Normally, moisture contents will be less than 9%, preferably less than 7%. The proportion of alkali metal bicarbonate to alkali metal carbonate, by weight, will generally be within the range of 1:0.4 to 1:0.8. The mixed product is preferably made by a method which results in a substantial content, e.g., 10 to 90% of Wegscheider's salt, with any balance being sodium mono- and/or bicarbonate. Such product is of excellent sorptive powers for liquid nonionic detergent and may be readily converted into a suitable base for a zeolite builder powder coating. A method for the manufacture of a mixed carbonate-bicarbonate product used successfully is shown in United States patent 3,944,500 of Gancy et al. A useful mixed carbonate-bicarbonate of the type described is available from Allied Chemical Corporation under the name Snowlite*. Although the method of the patent is a preferable one the mixed carbonate-bicarbonate beads may be made by other techniques, providing *Trade mark ' '. ,,~

38~9 that the end product is essentially the same.
Nonionic detergents include those described at length in McCutcheon's Detergents and Emulsifiers, 1973 Annual and in Surface active Agents, Vol. II, by Schwartz, Perry and Berch (Interscience Publishers, 1958). Such nonionic detergents which are useful in the present invention are usually liquid or paste-like solids at room temperature (20C.) which are either sufficiently water soluble to dissolve promptly in ~ater and/or are liquid at the temperature of the wash water, as when that temperature is above 40C. While the nonionic detergent employed will normally be one which is either liquid or pasty at room temperature, often preference will be given to normally liquid products because these readily penetrate into the interiors of the base particles, surprisingly leaving little or no material at the surfaces thereof, thus avoiding any tackiness due to presence of the nonionic detergent at the particle surfaces. The use of the normally liquid nonionic detergents allows room temperature application of the nonionic material to the base particles and avoids problems encountered due to any premature solidification of the nonionic or due to the presence of a pasty material near the surfaces thereof, which can be the result of undesired quick cooling of such nonionic de1-ergent before it has satisfactorily penetrated into the interior of the base particle.
Thus, although it would have been expected that one would prefer to employ a solid nonionic detergent or at least one which is normally pasty or semi-solid because it would be considered that such would be less liable to make a tacky product or poor flow properties and . , ~

~z~

susceptibility toward lumping or setting on storage than liquid nonionic detergents this is not the case. If the base beads are kept warm enough and the nonionic detergent is applied in liquid state, as may be effected when normally solid or pasty nonionic detergent is heated sufficiently, the product resulting, providing that penetration into the base bead interior is sufficient, will be as good as the preferred liquid nonionic detergent-base bead compositions with respect to flow and non-lumping properties but even in such case the liquid nonionic detergent is more amenable to being dispersed readily in aqueous media and therefore is more quickly effective in wash water. Generally, if a normally pasty, semi-solid or solid nonionic detergent is employed, when it is applied to the base beads it will be in the liquid state and usually will be at a temperature below 50 or 60C, always below 70C and preferably below 45C. For example, when a normally solid nonionic detergent such as Alfonic* 1618-65 is employed, it will be heated so as to be a liquid upon application but when Neodol* 25-6.5 or 25-7 is used heating will be unnecessary, providing that room temperature application, such as at 25C, is effected.
The typical useful nonionic detergents are the poly-(lower alkenoxy) derivatives that are usually prepared by the condensation of ethylene oxide and a higher fatty alcohol. The higher fatty alcohols will be of an average of 10 to 18 carbon atoms, preferably 12 to 15 carbon atoms, e.g., 12.5 carbon atoms, per mol and the e~hylene oxide content will be such that about 5 to 12 mols, preferably 6 to 7 mols thereof, e.g., *Trademark - 6 -1~2~8~

6.5 mols, will be present per mol of nonionic detergent.
Typical commercial nonionic detergents suitable for use in the invention include Neodol ~ 23-6.5, an ethoxylation product (having an average of about 6.5 ethylene oxide units per mol) of a 12 to 13 carbon atoms (average) chain fatty alcohol and Neodol 25-7, a 12 to 15 carbon atom chain fatty alcohol ethoxylated with an average of about 7 ethylene oxide units per mol, both of which are made by Shell Chemical Company.
Although it is not an essential component of the present compositions, it is also highly preferable that an additional builder salt, sodium silicate, should be present.
The most acceptable form of such material is a particulate hydrous sodium silicate, of Na20:SiO2 ratio in the range of 1:1.8 to 1:3.2, preferably about 1:2 to 1:2.~, hydrated by about 10 to 25% of moisture, preferably 15 to 20%, e.g., 18%. Such material will desirably be in the same ranges of particle sizes as described previously for the mixed bicarbonate and carbonate.
Various adjuvants, both functional and aesthetic, may be included in the present compositions, such as bleaches, e.g., sodium perborate; colorants, e.g., pigments, dyes;
fluorescent brighteners, e.g., stilbene brighteners; anti-redeposition agents, e.g., sodium carboxymethylcellulose; foam stabilizers, e.g., alkanolamides, such as lauric myristic diethanolamide; enzymes, e.g., proteases; skin protecting and conditioning agents, such as water soluble proteins of :7~

low molecular weight, obtained by hydrolysis of proteinaceous materials, such as animal hair, hides, gelatin, collagen;
foam destroyers, e.g., silicones; bactericides, e.g., hexa-chlorophene; and perfumes. Usually such adjuvants and any supplemental builders will be admixed with the other components at a particular stage in the manufacturing process which is most suitable, which usually depends on the nature of the adjuvant and its physical state. Particularly desirable will be additions which help to stabilize the adjuvant or other components of the product and/or which increase the power of the carbonate-bicarbonate mixture to absorb nonionic detergent.
The proportions of bicarbonate-carbonate particles and nonionic detergent in the product should be chosen to result in the composition made being of satisfactory cleaning power and the particles being free flowing and of desired high bulk density. Such proportions are normally within the range of 15 to 22% of nonionic detergent, with the balance being mixed bicarbonate-carbonate beads, supplemental builders, such as silicate (alkali metal silicate) e.g., sodium silicate, if present, and adjuvants and moisture. Preferably, the alkali metal bicarbonate component, sodium bicarbonate, in Wegscheiderite or otherwise, is from 30 to 45%, more preferably 30 to 40%, the carbonate content, in Wegscheiderite or otherwise, is preferably 15 to 30%, more preferably 15 to 25%, the moisture content is preferably 1 to 7%, more preferably 1 to 5%, the silicate content is 5 to 15%, preferably 8 to 12%

"

and the total of adjuvants is 3 to 10%, preferably 4 to 8%.
A specifically preferred formulation includes 20% of nonionic detergent, 38% of sodium bicarbonate, 23% of sodium carbonate, 10% of hydrous sodium silicate, 5% of adjuvants and 4% of moisture. The moisture content is that removable from the product when it is held in a 105C oven for five minutes but normally excludes the water of hydration of the hydrous sodium silicate.
The bulk density of ~he product resulting will be at least about 0.6 g/ml, preferably being in the range of 0.6 to 0.7 g/ml. The particle sizes of the product will usually be in the range of 4 to lO0 mesh ~United States Standard Sieve Series), preferably lO to 60 mesh and most preferably about 20 to 40 mesh. However, finer component particles may be employed initially and may be agglomerated up to the mentioned desired sizes. Generally, the materials within the mesh ranges given will constitute a mixture of products of different particle sizes within such ranges (this is usual for the various particulate materials described herein) rather than a product of a single particle size.
In the manufacture of the starting carbonate-bicarbonate mix particles the method of United States patent 3,944,500 may be employed and the product ~hereof, identified by the trade name Snowlite*, obtainable from Allied Chemical Corporation, is preferably used. A typical analysis for *Trademark - 9 -~2~38~

Snowlite I is 35% Na2C03, 58.5% NaHC03 and 6.5% H20 whereas that for another such product, Snowlite II, is 30.0, 66.5 and 3.5%, respectively. Screen analyses (percentages on No's. lO, 40, 60 and 100 screens) are 0.2, 67.6, 96.9, 99.0 and 0.7, 60.7, 90.7 and 97.0, respectively. Bulk densities (g/ml~ are 0.51 and 0.48 respectively (tamped) and 0.42 and 0.38 (untamped). Friability ls especially low for Snowlite I ~2.5% by Allied Chemical Corp. test Na 17-35) so it is sometimes preferred. In some cases other components of the final product may be included in the mix of bicarbonate and Wegscheider's salt being processed by the patent method, providing that they are stable and do not adversely react or interfere with the making of the carbonate-bicarbonate product. Normally the carbonate-bicarbonate particles will contain at least 60%, preferably 70% and more preferably from 80 to 95% or more of bicarbonate and carbonate, when such other such adjuvants are present, 5 to 15% of sodium silicate and/or 0.1 to 5% of fluorescent brightener and/or 0.2 to 1.5% of anti-redeposition agent, sometimes with additional water too, to bring the water contents of the products within the ranges previously mentioned.
The free flowing, phosphate-free, particulate, high bulk density, heavy duty laundry detergents of this invention are easily made by admixing the described sodium carbona~e-sodium bicarbonate particles with a nonionic .~

detergent in liquid form. The detergent penetrates the carbonate-bicarbonate particles but may leave a portion thereof on the particle surfaces to which any subsequently admixed component material may adhere. The nonionic detergent, normally a liquid or pasty one, preferably being liquid, as previously recited, is preferably sprayed onto the moving surfaces of the carbonate-bicarbonate particles, after which the other powdered components may be admixed therewith, although preferably they are mixed with the bicarbonate-carbonate mixture before spraying thereon of the nonionic. The proportions of materials utilized are such that the product made will be of a desired, previously described composition.
The initial spraying or other mixing of nonionic detergent with the carbonate-bicarbonate particles is normally effected with the particles at about room temperature (20 to 25C) but the temperature may vary over the ranges of 10 to 40 or 50 C. The spraying and admixing may take as little as 1 to 5 minutes and mixing may be continued after completion of the spraying for a period of 0 to 10 minutes, preferably 1 to 5 minutes. The normally liquid higher fatty alcohol-polyethylene oxide condensation product being sprayed onto the surfaces of the moving beads is preferably at room temperature (20 to 25C) but if normally pasty or solid, is usually heated to an elevated temperature such as 30 to 70C, preferably 40 to 60C, so that it is liquid and is sprayed onto the moving surfaces or otherwise applied to them so as to distribute it over them and promote adsorption of the liquid into the porous particles. Additionally, some agglomeration may be effected during the initial mixing, apparently being due to adhesion or cohesion between some of the finer particles present which have "excessive" amounts of liquid nonionic detergent at the surfaces thereof. During such agglomeration such particles may be increased in size to sizes approximately in the range of final product, although by control af the process agglomeration or excessive agglomeration is avoidable. Thus, often it is found that merely increasing the mixing speed prevents agglomeration and in some instances increasing the mixing time also accomplishes such purpose.
Preferably the mixing and spraying of the nonionic detergent onto the moving particles are effected in a rotating drum or tube inclined at a slight angle, such as 5 to 15 . The rotational speed may be any that is suitable, such as 5 to 50 r.p.m. The spraying of the nonionic detergent will normally be such as to produce fine droplets of such detergent, such as those of diameters in the ~0 to 200 micron diameter range, preferably 50 to 100 microns but other suitable spray droplet sizes may also be produced and in many cases the nonionic may be blended ~ith the mixed carbonate-bicarbonate particles aftPr being dropped or poured onto the moving surface thereof. In such cases one may employ a higher speed or higher energy mixer such as a Lodige mixer, operating at comparatively low speed, or a twin shell or similar type mixer, to prevent excessive agglomeration of particles caused by addition of the larger droplets or streams of nonionic detergent. As j:, ~ ' 4 ~Z~3B~

was previously indicated, although it is not preferred, sorptive carbonate-bicarbonate particles could be made by methods other than those herein described, wherein more angular products result, but it is highly desirable for the particles to be flowable and most preferably they are somewhat rounded, preferably spherical.
After completion of the spraying of the nonionic detergent onto the base beads, possibly mixed with powdered silicate and possibly also mixed with other powdered components, such as anti-redeposition agent(s) and adjuvants, the product, which will usually be of a moisture content of 1 to 10%, preferably 1 to 7% ~excluding water of hydration in the hydrous silicate particles), is ready for packaging. Various adjuvants can be incorporated in the product by direct admixing at suitable points in the process or by inclusion - with suitable components. Althoucgh the adjuvant content will normally be lower, as previously described, if a perborate bleach is utilized in the composition the percentage thereof may be increased to an effective bleaching amount, which can be as high as 30% of the product, normally with the proportions of the other components being proportionately diminished accordingly. Such perborate may be co-mixed with the carbonate-bicarbonate mixture or may be post-added to the nonionic-treated mix or to the final product. Colorants, perfumes and other adjuvants may be admixed with the various . , BZ~

components and mixtures during manufacture or after completion thereof, too. In one aspect of the invention perfume may be blended with the nonionic detergent before spraying of the nonionic detergent onto the surface active agent-free carbonate-bicarbonate mixture. However, normally perfume is post-added because it is found that its presence is more noticeable to the consumer in such case.
The products of this invention have significant advantages over phosphate-containing and`low phosphate heavy duty detergents because they are satisfactorily detersive against a variety of soils normally found on household items to be washed and yet comply with legislative and administrative rulings restricting the use of phosphates in detergents. Thus, a product of the present formula may be employed nationwide and there is no need for several formulations and restricted shipments of detergent compositions to different areas in the country. The satisfactory detergency is due to the presence of a sufficient content of nonionic organic detergent and the mixed carbonate-bicarbonate builder salts. Normally, one might expect that the comparatively high concentration of nonionic detergent which in itself is usually liquid or pasty, would cause the product to be "lazy" or poorly flowing, with a tendency to cake on storage, but due to the application of the nonionic detergent to the mixed carbonate-bicarbonate beads in liquid form and the special character of the carbonate-bicarbonate particles which are otherwise devoid of organic - 1~ -. , , surface active or detersive agent content, the normally liquid or melted nonionic detergent penetrates into the interiors of the base particles and does not form an objection-ably tacky coating on the particle surfaces that could interfere with flow. Thus, a very free flowing and non-caking product is obtainable, with the mixture of carbonate and bicarbonate in the base beads providing the builder action for the present compositions and at the same time being a desirable base for sorption of the nonionic detergent. The presence of the bicarbonate lowers the normally excessive high pH
that would otherwise be obtained by use of a carbonate alone and by diminishing the content of carbonate in the product -makes the product safer for use. The presence of the carbonate in Wegscheiderite also irnproves safety. Specifically, the lower carbonate content in the final product, generally lower than 30% of the product, lS acceptably low so that the product is not considered to be toxic to infants or young children who might accidentally ingest it. With at least 10%
of the bicarbonate-carbonate mix, preferably 20 to 60% thereof, being Wegscheiderite, such degree of safety is further increased.
; Higher concentrations of carbonates in detergent products are sometimes objectionable because of the possibility that accidental ingestion of significant quantities thereof, for example, more than 5 grams per kg of body weight of a child, can cause esophageal harm. ~ecause of the excellent sorption ~2~

of the nonionic detergent by the carbonate-bicarbonate beads the surfaces of the beads do not become tacky and under average humidities the compositions may be marketed without the use of special wax coated barrier cartons and do not require the presence of any drying agent or coating thereof on the beads to maintain flowability. Low moisture content beads may be made because the nonionic detergent present prevents the particles from being objectionably friable. Because the beads are porous when they are added to wash water the water readily penetrates into them, dissolving the nonionic detergent, which further wets the beads and promotes solubility of the carbonate and bicarbonate. Similarly, dissolving of the carbonate helps to break up the beads and further assists in dissolving the less soluble bicarbonate. The comparatively large sizes of the product and of the starting materials are somewhat unusual but result in free flowing particles which - still dissolve rapidly and are of high bulk density. Partly because of the comparatively large particle sizes of the carbonate-bicarbonate particles better absorption of nonionic detergent resultsS not objectionable paste formation.
The properties of the present compositions are unexpectedly superior to those of other builder compositions that have been employed in the past to make built anionic detergent-based products. For example, although phosphates such as pentasodium tripolyphosphate have been produced in a 1~2~

form which readily absorbs nonionic detergent to produce a high bulk density product that still remains free flowing, soda ash, potassium carbonate, hy-drous sodium silicate and various mixtures of soda ash and sodium silicate have been found to produce poorly flowing products which often appear oily or damp and sometimes have a tendency to lump or cake, too.
The following examples illustrate various embodiments of the in-vention but it should, not be considered as limited to them. Unless other-wise mentioned all parts are by weight and all temperatures are in C.

Percent a Nonionic detergent (condensation product of higher 20.0 fatty alcohol of 12-13 carbon atoms with polyethylene oxide of 6 to 7 mols of ethylene oxide per mole of higher fatty alcohol) b Mixed sodium bicarbonate-sodium carbonate builder contain- 65.0 ing 66.5% sodium bicarbonate, 30% sodium carbonate and 3.5% water, including at least 10% Wegscheiderite c Hydrous sodium silicate (Na20:SiO2 = 1:2, containing 10.0 18% H20) d Fluorescent brightener 2.0 Sodium carboxymethylcellulose 1.0 e Proteolytic enzyme 1.5 Ultramarine Blue 0.2 Perfume 0.3 100 .0 ~z~

a Neodol* 23-6.5, mfd. by Shell Chemical Company b Snowlite* II, mfd. by Allied Chemical Corporation according to the process of United States patent 3,944,500 (Gancy et al.) c Britesil* ~l20, mfd. by Philadelphia Quartz Corp.
d Tinopal* 5BM, mfd. by Ciba-Geigy Corp.
e Alcalase*, mfd. by Novo Industries, Inc.
The mixed sodium bicarbonate-sodium carbonate builder particles, of particle sizes previously described in this specification, and containing about 20% Wegscheiderite, together with sodium bicarbonate and sodium carbonate, are charged at room temperature (25C), together with the other particulate solid components of the product, to an inclined drum of about 8 inclination, rotating at a speed of about 40 r.p.m. The hydrous sodium silicate particles are of sizes (effective diameters) within the 4 to 100 mesh range but the balance of the particulate solids content of the composition is more finely divided, normally being in the 60 to 160 mesh (Sieve No.) range. However, in comparable experiments the particuIate adjuvants, except for the pigments, are in the 4 to lO0 mesh range, too and similar results are obtainable.
After pre-mixing the various particulate solid components of the product over a period of about one to three minutes the nonionic detergent is sprayed onto the moving surfaces of the particles over a period of about *Trademark - 18 -~z~

three minutes, after which mixing in the drum is continued for another five minutes. The nonionic spray is in the form of droplets largely in the range of 50 to 100 microns and is at a temperature of 25C, suficient for penetration of the beads onto which it is sprayed. Subsequently, the perfume is sprayed onto the product over a period of about one minute and the resulting detergent composition is packaged and stored, ready for shipment and sale. The particles of product are in the 4 to 40 mesh range, the untamped bulk density thereof is about 0.7 g/ml and the flowability is about 80% of that of sand of comparable particle size. The stored composition does not cake or develop objectionable lumps on storage and when the package is opened after three months' storage under average ambient conditions the detergent pours readily and the bulk density is found to remain at about 0.7 g/ml.
When subjected to actual property evaluation and washing tests or practical ]aundry tests it is found that the detergent composition is non-dusting, free flowing, non-caking and of acceptable detergency for commercial applications, comparing favorably to tripolyphosphate-built products of similar active ingredient contents. The carbonate does not produce excess alkalinity, due to the presence of the bicarbonate, which buffers the carbonate and results in a wash water having a pH of about 9.5 at both 0.07% and 0.15% product concentrations. Also, because of the comparatively low ~, ~z~
content of carbonate the product is safe for commerical marketing and is not considered to be intolerably hazardous when accidentally ingested by young children.
In a comparative experiment finely divided sodium carbonate and sodium bicarbonate powders, of particle sizes in the 170 to 270 mesh range are used and agglomerated to a particle size in the 4 to 40 mesh range by preliminary treatment with 5% by weight of a 20% cornstarch paste ~aqueous) sprayed onto moving particles of the powdered carbonate and bicarbonate in the same mixing drum previously described, over a period of about three minutes, with the drum moving at slow speed, e.g., 10 r.p.m. Tne product resulting is a useful detergent at the same concentration used for the previous experiment (1/4 cup or about 45 grams per 65 liter tub of wash water), washing a charge of about 4 kg of soiled garments, but is not as free flowing as the previously described detergent. When only sodium bicarbonate is used as a starting builder salt the product does not wash as well as the described preferred product and when the carbonate alone is employed the product is more alkaline than desirable and is not as free flowing. However, the carbonate-containing composition does have utility as a detergent in applications wherein higher pH's can be tolerated, although on the retail market it would not be as acceptable as the preferred products of the present invention because of its comparatively poor flow characteristics, higher pH and comparative toxicity when accidentally ingested.

Percent Snowlite I 70.0 Hydrous sodium silicate ~Na20:SiO2 = 1:2, 10.0 containing 18% H20) Neodol 25-7 20.0 100 .0 The Snowlite particles are charged at room temperature to the inclined drum of Example 1 or to comparable twin shell, V- or Patterson-Kelley blenders, the hydrous silicate, desirably of approximately the same particle size, is added to the drum, while mixing, over a period of about two minutes and mixing is continued for another minute to blend the silicate evenly with the carbonate-bicarbonate particles.
Then, over a period of another five minutes the nonionic detergent, at a temperature of about 30C, is sprayed onto the moving surfaces of the particles. The product resulting is an excellent concentrated heavy duty, non-phosphate detergent, useful for washing of laundry at a concentration of 0.05 to 0.2% in the wash water (0.07% and 0.15% are most frequently employed in top-loading washing machines). The product is of a bulk density of about 0.6 g/ml and is free flowing after normal storage, having a flow rate of about 80% that of sand of similar particle size. Such flow rate is superior to that of most of the spray dried heavy duty detergent compositions commercially marketed today. Comparable products are made utilizing Neodol 45-11 and Alfonic 1618-65 instead of Neodol 25-7 but such have to be maintained at 1~2~

elevated temperatures, e.g., 45C, to promote penetrations into the interiors of the base particles, for reasons previously described.
When the sodium silicate is omitted the loss of its building effect is noted, as is the loss of its anti-corrosion activity but the product made, with additional Snowlite I
replacing the silicate, is a useful detergent of similar flow, bulk density and storage properties.

Percent Snowlite I 35.0 Snowlite II 35.0 Neodol 23-6.5 20.0 Hydrous sodium silicate 10.0 ~as in Examples 1 and 2) 100 . O
The manufacturing procedure of Example 2 is followed except that the two different Snowlite products are pre-blended over a period of about two minutes. The product resulting is an excellent heavy duty detergent, free flowing, non-tacky, non-lumping on storage and of desirable comparatively high bulk density (0.6 g/ml).
When Neodol 23-6.5 is replaced with Neodol 25-7 essen-tially the same type of product results. When the hydrous sodium silicate is replaced with one of Na20:SiO2 ratio of 1:2.4 a similar good product results but when it is omitted its anti-corrosion and building activities are not obtained, as reported in Example 2. When the adjuvants of Example 1 are incorporated, as described in such example, replacing 2.5% of each of the 1~2~

Snowlites, a product essentially like that of Example 1 is obtained. To make a bleaching detergent composition the contents of the Snowlites* are reduced to 28% each, the content of nonionic detergent is reduced to 16% and the content of silicate is reduced to 8%, with 20% of sodium perborate being admixed with the materials in the tumbling drum prior to or subsequent to the spraying of the nonionic detergent and prior to application of the perfume. The product obtained, when utilized in wash water at elevated temperatures sufficiently high to release oxygen from the perborate, is of improved stain-bleaching properties. The bulk density and flowability are about the same as those for other compositions of this example.

In this comparative example there are substituted for the Snowlite*-mixed bicarbonate-carbonate products of Examples 1-3 the following builder materials:
Hydrous sodium silicate (Zeopol* 100, mfd. by Huber Corp.) Light granular soda ash (Flozan*, mfd. by Diamond-Shamrock Corp) Dense soda ash (Grade 260, mfd. by FMC Corp~
Soda Ash - sodium silicate mixture (Flosil* A, mfd. by Philadelphia Quartz Co.
Soda ash - sodium silicate mixture (Sodasil*, mfd. by Witco Corp.) Granular ~2CO3.

*Trade mark ~Zt~8~

The products resulting, unlike those obtained when the Snowlites are employed, which are very free-flowing granules, are poorly flowing and unsatisfactory for commercial marketing. Those con~aining Zeopol 100 are generally lumpy, of lazy flo~ characteristics and appear to be damp powders.
Those containing Flozan are lazy powders and those based on dense soda ash become oily masses during manufacture. The balance are of lazy flow characteristics and appear to be oily powders.
The invention has been described with respect to working examples and illustrations thereof but is not to be limited to these because it is evident that one of skill in the art with access to the present specification will be able to employ substitutes and equivalents without departing from the spirit or scope of the invention.

Claims (4)

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

1. A phosphate-free, free flowing particulate heavy duty laundry detergent of bulk density of at least about 0.6 g./cc., moisture content below 10% and particle sizes in the range of 4 to 100 mesh which comprises nucleus particles of mixed alkali metal bicarbonate and alkali metal carbonate in which the pro-portion of bicarbonate to carbonate is in the range of 1:0.4 to 1:0.8, containing a normally liquid or pasty nonionic detergent in such quantity that the percentage of such detergent in the product is from 15 to 22% and the proportion of nonionic detergent to the total of alkali metal bicarbonate and alkali metal carbonate is in the range of 1:2.5 to 1:4, and hydrous sodium silicate.

2. A heavy duty laundry detergent according to claim 1 wherein the mixture of alkali metal bicarbonate and alkali metal carbonate is a mixture of sodium bicarbonate and sodium carbonate containing at least 10% of Wegscheider's salt, the nonionic detergent is a higher fatty alcoholpolyethylene oxide condensation product wherein the higher fatty alcohol is of 10 to 18 carbon atoms and the polyethylene oxide is of 5 to 12 moles of ethylene oxide per mol of higher fatty alcohol, and the hydrous sodium silicate is of Na2O:SiO2 ratio in the range of 1:1.8 to 1 3.2 and is hydrated by about 10 to 25% moisture.

3. A heavy duty laundry detergent according to claim 2 wherein the nonionic detergent is a higher fatty alcohol-polyethylene oxide condensation product in which the higher fatty alcohol is of 12 to 15 carbon atoms and the polyethylene oxide is of 6 to 7 mols of ethylene oxide per mol of higher fatty alcohol and the percentage of alkali metal bicarbonate, including that in Wegscheider's salt, is from 30 to 45% and that of the carbonate, including that in Wegscheider's salt, is from 15 to 30% and which includes from 5 to 15% of hydrous sodium silicate of Na2O:SiO2 ratio of about 1:2 and of about 15 to 20% moisture content, 3 to 10% of adjuvants and 1 to 7% of moisture.

4. A heavy duty laundry detergent according to claim 3 which has a flow rate about 80% of that of similarly sized sand and a bulk density of about 0.7 g./ml. wherein the nonionic detergent is a condensation product of a higher fatty alcohol of 12 to 13 carbon atoms and 6.5 moles of ethylene oxide, the mixture of sodium bicarbonate and sodium carbonate is one con-taining about 30% of sodium carbonate, 66.5% of sodium bicarbonate and 3.5% of moisture and the hydrous sodium silicate is of Na2O:SiO2 ratio of about 1:2 and includes about 13% of water and which comprises about 20% of the nonionic detergent, about 65% of the mixture of sodium bicarbonate, sodium carbonate and water, including at least 10% of Wegscheider's salt, about 10% of hydrous sodium silicate and about 5% of adjuvants.