IE47263B1 - Detergent compositions - Google Patents

Abstract

Free flowing phosphate-free particulate detergent compositions suitable for heavy duty laundering, have a bulk density of at least 0.6 g/ml and particle sizes in the 4 to 120 mesh (U.S.) range and comprise particles of alkali metal carbonate and alkali metal bicarbonate containing a normally liquid or pasty nonionic detergent. The compositions may be prepared by spray-drying.

Description

This invention relates to particulate detergent compositions suitable for heavy duty laundering, and . to their manufacture.

According to one aspect of the invention a free flowing phosphate-free particulate detergent composition suitable for heavy duty laundering is of high bulk density, namely of at least 0.6 g/ml, and of particle . sizes in the 4 to 120 mesh range, and it comprises spray dried particles of alkali metal carbonate and alkali metal bicarbonate containing a normally liquid or pasty nonionic detergent introduced after the spray drying.

All mesh sizes herein are U.S. Sieve Series, and . all percentages and other proportions are by weight unless otherwise indicated.

Particles of bulk density lower than about 0.6 g/ml have been made but are not preferred because greater volumes;-are required for washing and therefore . convenience of use and packaging options are sacrificed.

' According to another aspect of the invention a method of making such compositions comprises spray drying an-aqueous crutcher mix of alkali metal bicarbonate, usually with alkali metal carbonate present . too, to produce beads of such alkali metal bicarbonate mixed with alkali metal carbonate decomposition product thereof, of a particle size in the 4 to 120 mesh range, and applying to the particles a normally liquid or pasty nonionic detergent, in liquid state, so as to cause . the detergent to penetrate into interiors of the particles and increase their bulk density. The application of the nonionic detergent may he effected by admixing it with the particles or by spraying it onto moving surfaces of the alkali metal carbonate-alkali metal . bicarbonate spray dried beads. Preferably at least 10% of Wegscheider's salt is present in the beads.

The products of this invention are excellent phosphate-free particulate detergent compositions of comparatively high bulk densities and acceptably . large particle sizes, making it possible to utilize small volumes thereof, e.g. from 50 to 125 ml, for an average wash in an automatic washing machine.

The alkali metal carbonate and alkali metal bicarbonate employed may be charged to a crutcher or . other suitable mixer as separate particles, or with both carbonate and bicarbonate included in the same individual beads, or as double salts, or as a mix of such materials, but alkali metal bicarbonate only may be charged to the crutcher, the desired proportion . of carbonate in the spray dried particles being obtained by decomposition of some of the bicarbonate. While normally powders of particle sizes in the 20 to 100 range will be utilized, powders of particle sizes up to 4 mesh and as fine as 200 mesh may be employed, providing · that they dissolve and/or disperse readily in the aqueous crutcher mix. Salts such as sodium sesquicarbonate and Wegscheider's salt may he used, as may be various hydrates of alkali metal carbonates and bicarbonates. Although of the alkali metal salts both sodium and . potassium salts are preferred, the sodium salts are most preferred.

The nonionic detergents are listed at length in McCutcheon's Detergents and Emulsifiers, 1973 Annual and in the textbook Surface Active Agents, Vol. Il, . by Schwartz, Perry and Berch (Interscience Publishers, 1958), Such detergents may he liquid or pasty (which term includes waxy) solids at room temperature (20°C) and are usually either sufficiently water-soluble to dissolve promptly in water or will quickly melt at . tbe temperature of wash water (and the crutcher), as when such temperature is ahove 30 or 40°C. The nonionics employed will usually be those which are liquid at room temperature, but those which are normally pasty but liquefiable at elevated temperature, e.g., 35 to 70C, such as 40 to , 60°C, at which they may be applied to the beads and absorbed by them, are also useful. The liquid nonionic detergents are often preferred because they penetrate into the beads very rapidly, without the need to heat either the detergent or the beads. One of the . unexpectedly beneficial qualities of the beads made is that they absorb and hold comparatively large quantities of liquid nonionic detergent without becoming tacky and poorly flowing, even after prolonged storage. The normally pasty nonionics, once they penetrate to the . interiors of the carbonate-bicarbonate particles, are also useful in making free flowing and non-tacky products, but to promote such initial penetration they must he liquefied, which requires heating and in some instances the base beads onto which they are sprayed are also . heated.

Typical useful nonionic detergents are the polyflower alkenoxy) derivatives that are usually prepared by the condensation of lower (2 to 4 carbon atoms) alkylene oxide, e.g. ethylene oxide or propylene . oxide (with enough ethylene oxide to make a watersoluble product), with a compound having a hydrophobic hydrocarbon chain and containing one or more active hydrogen atoms, such as higher (at least Cg) alkyl phenols, higher fatty acids, higher fatty mercaptans, . higher fatty amines and higher fatty polyols and alcohols, e.g. fatty alcohols having from 8 to 20 or from 10 or 12 to 18 carbon atoms in an alkyl chain and alkoxylated with an average of about 3 to 30, preferably 3 to 20 and more preferably 5 to 12 lower alkylene . oxide, e.g. ethylene oxide, units. Preferred nonionic detergents are those respresented by the formula R0(C2H40)nH wherein R is the residue of a linear saturated primary or secondary alcohol (an alkyl) of 10 to 18 carbon . atoms and n is an integer from 5 to 20 or 5 to 12. The preferred nonionic detergents may be referred to as higher fatty alcohol polyoxyethylene ethanols (the terminal ethanolic part of these ethers is included in the number of oxyethylene groups counted in the . mols of the nonionic detergent). Typical commercial nonionic detergents suitable for use in the invention include Neodol 23-6.5, an ethoxylation product with an average of about 6.5 mols of ethylene oxide per mol of a 12 to 13 carbon atom chain fatty alcohol, Ueodol 50. 25-7, a 12 to 15 carbon atom chain fatty alcohol 4*7263 etho>ylated with an average of 7 of the ethylene oxide units, Keodol 45-1111 > an ethoxylation product (having an average of about 11 ethylene oxide units) of a 14 to 15 carbon atom (average) chain fatty . alcohol (all made hy Shell Chemical Company U.S.A.) and of these the first two are most preferred. Thus, the fatty alcohol is preferably of 12 to 15 carbon atoms and the polyoxyethylene is of 5 to 8 mols of ethylene oxide per mol of fatty alcohol.

. The composition may contain an auxiliary builder or builders such as an alkali metal silicate. The alkali metal silicate is preferably sodium silicate of Na^O-’SiO^ ratio in the range from 1:1.6 to 1:5-2, preferably from 1:1.8 to 1:5 and most preferably from . 1:2 to 1:2.4, e.g. 1:2.35· Such silicate may he added to the aqueous crutcher mix as an aqueous solution, usually containing about 40% of sodium silicate solids. Alternatively, other suitable silicates, such as hydrous sodium silicate, may he used. Such a product . Is sold as 3ritesil, manufactured by Philadelphia Quartz Company, U.S.A. and normally is of Ife20:Si02 ratio of about 1:2, having 20 to 24% of moisture in it. The silicate auxiliary builder will usually be of particle sizes (effective diameters) in the range . from 10 to 150 mesh and substantially all, 97% or more, within the range from 10 to 100 mesh. When hydrous sodium silicate is utilized it may often be admixed with the carbonate-bicarbonate beads before spraying thereon the liquid nonionic detergent hut It can be post-added · to the carbonate-bicarbonate beads after they have absorbed the detergent.

In addition to the mentioned components oi the final product, in preferred compositions various adjuvants will also be present. For example, to improve - cleaning, a proteolytic enzyme or equivalent enzyme may he post-added (normally such enzymes are not included in the crutcher mix because spray drying has an inactivating effect on them). Such enzymes are described in Principles of Biochemistry by White, . Handler, Smith and Stetten (1954).

Another preferred adjuvant is a fluorescent brightener. Fluorescent brighteners are well known in the detergent art and usually are reaction products of cyanuric chloride and the disodium salt of diamino . stilbene disulphonic acid, benzidine sulphone disulphonic acid, amino coumarins, diphenyl pyrazoline derivatives or naphthotriazolyl 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, 1967, especially at pages 3 to 5 thereof. Among such brighteners are *Tinopal 5BM (Geigy) *»Tinopal RBS, SOF (Ciba), and one known as Stilbene IJo. A, namely disodium 4,4'25 bis-(4-anilir.o-6-morpholine-s-triazine-2-ylamino)-2,2' stilbene disulphonate. Of these, Tinopal 5BM is preferred.

Various other adjuvants may be present in the crutcher mix or may be post-added, including foam . improvers, foam depressants, fungicides, antioxidants, *Tinopal is a trade mark 47363 sanitizers, stabilizers, chelating agents, soil suspending agents, soil anti-redeposition agents, colorants (pigments and dyes), bleaches and perfumes. Such materials are well-known in the art and need not he . recited at length.

The proportion of alkali metal carbonate to alkali metal bicarbonate generally should be within the range from 2:1 to 1:5, s.g· preferably from 2:1 to 1:3, more preferably from 1:0.8 to 1:3 and most preferably about . 1:1.

The sum of the weights of carbonate and bicarbonate will normally be from 40% to 90% of the weight of the composition, preferably from 50% to 70%, more preferably from 55% to 65% and most preferably about . 60% or about 62% of the composition, while the nonionic detergent content will normally be from 10% to 30%, preferably from 15% to 25%, e.g. 15% to 22%, more preferably from 18% to 22% and most preferably about 20%. In some cases even as much as 35% or 40% of . nonionic detergent, usually as a normally solid detergent in such cases, may he present. The silicate content, while it may be as high as 25% in some instances, will normally be from 3% or 5% to 20%, preferably from 5% to 15% and most preferably about 10%, while the . moisture content, although variable to suit particular circumstances, will normally be from 2% to 12%, preferably from 2% to 10%, more preferably from 3% to 6% and most preferably about 4% or 5%. The total of adjuvants, including fluorescent brightener, proteolytic enzyme . and anti-redeposition agent, when present, will usually 47363 not exceed 10% of the composition, preferably being less than 5% and more preferably less than 5%, the percentages of individual components being less than 3% and preferably less than 1% or 2% each. Thus, the . fluorescent brightener content will normally be in the range from 0.05% to 3%, preferably from 1% to 2.5%, the proteolytic enzyme content (including the normal carrier for such enzyme) will be from 0,5% to 3%, preferably from 1% to 2%, the pigment content will be . from 0.1% to 0.4% and the perfume content will be from 0.1% to 0.4%, when such adjuvants are present.

If desirable, the percentage of anti-redeposition agent may be as high as 3% but normally the percentage thereof, if present, will be from 0.5% to 2%. If a bleaching . detergent is desired, as much as 30% of sodium perborate, usually as the common hydrate, NaBOg.

H202 . or NaBOj . 4H20, called sodium perborate tetrahydrate, may be present and the proportions of other materials previously described will be diminished . proportionately. Preferably the proportion of perborate present will be from 18% to 25%. Because of the heat sensitivity of the perborate it should be post-added to the spray dried carbonate-bicarbonate particles, either before or after application of the nonionic detergent, · and will be of similar particle size, e.g. from 4 to 100 mesh. Instead of perborate, other compatible bleaches in similar or otherwise appropriate amounts may be employed, e.g. sodium percarbonate, potassium persulphate or sodium dichloroisocyanurate.

. The high bulk density particulate detergent composition of the invention will usually be in free flowing rounded bead form like that of other spray dried products, although the bead interior may be virtually honeycombed. The particle sizes of the beads are in the range from 4 to 120, preferably 4 or 6 to 100 sieves, and more preferably 8 to 100, with less than 10%, preferably less than 5% and more preferably less than 1% of the product being outside such ranges.

Preferred narrower ranges are 10 to 60 mesh, e.g. 20 to 40 mesh. The bulk density of the finished detergent composition is at least 0.6 g/ml, preferably at least 0.65 g/ml and most preferably-in the 0.65 to 0.8 or 0.9 g/ml range, e.g. 0.67 g/ml· The flow rates of the compositions usually will be greater than 70% of the rate of free flowing sand of similar particle size, normally being from 70% to 90% thereof, preferably from 75% to 90% thereof.

In the manufacture of the compositions it is important that a sorptive bead be made for rapid pentration by nonionic detergent and absorption of the detergent in the bead interior. Such sorption should he sufficient for the nonionic detergent to he held in the bead interior, whether liquid or pasty, and therefore not to tend to cause caking of the beads or poor flow properties, despite lengthy storage. Although sodium carbonate has sometimes been found to be a satisfactory sorbent for many nonionic detergents, products made with it alone 4726 as the builder, at least in the quantities needed to make compositions of the type which are acceptably detersive and sorptive, tend to have objectionably high pH's. The presence of bicarbonate with the . carbonate has a buffering effect and lowers the pH satisfactorily. Even so, when the content of carbonate is too high, despite the lowering of the pH by bicarbonate, the quantity of carbonate in the composition can make it harmful (it may burn the esophagus) , if accidentally ingested, as by a child or infant. At the particular ratios of carbonate to bicarbonate previously described, such as 1:0.8 to 1:3, it has been found that beneficial cleaning effects result,, compared with similar products in which carbonate is employed . exclusively, with no bicarbonate present. Some of the desirable physical properties of the product, includin sorption characteristics, may be enhanced by the decomposition of a portion of the bicarbonate during the manufacture of tiie spray dried carbonate-bicarbonate . beads, with the resulting escape of carbon dioxide from the product and/or neutralization of any excess or localized alkalinities by the carbonic acid released.

Thus, the manufacture of the base beads by spray drying of the carbonate-bicarbonate solution to result in a . product of certain proportions of carbonate and bicarbonate has desirable physical effects, produces an improved detergent composition and causes a lowering of pH and toxicity of the product.

The bulk density of spray dried carbonate-bicarbonate . beads, with or without silicate and other heat stable adjuvants present therein but before having nonionic detergent applied to them, will normally be in the range from 0.5 to 0.7 g/ml. The moisture content of such beads will usually be higher than the moisture . content in the final product due to the dilution of the final product by nonionic detergent and any other materials added to the spray-dried carbonate-bicarbonate heads. When hydrous sodium silicate is post-added to the carbonate-bicarbonate beads, either . before or after application of the nonionic detergent, allowance will be made for the content of moisture therein, normally, when there are no significant post-additions, the moisture content of the carbonatebicarbonate beads will be in the range from 2.5% or 3% . to 15%, preferably from 3· 5% to 12%.

The crutcher mix to be spray dried will normally include from 40% to 75%, e.g. about 50% of solids and from 25% to 60% of water. Preferably, the water content will be from 25% to 50% or 55%, the balance of the mix being non20. surface active solids. Of the solids content at least 80%, preferably at least 90% is a carbonate-bicarbonate mixture, the weight ratio of carbonate to bicarbonate charged to the crutcher being in the range from 1.8:1 to 1:10, preferably from 1:1 to 1:6. The crutcher . will usually be provided with heat exchange means so that the temperature of the mix may be regulated.

Normally such temperature is in a range from room temperature to 90°C, preferably from 20° to 70°C and most preferably from 45° to 65°C. Crutching times are . usually in the range of 5 minutes to one hour, preferably from 10 minutes to JO minutes. When the silicate is present in the crutcher mix the carbonate, bicarbonate and. water, plus any other non-surface active components to be included in the spray dried base beads, e.g. . fluorescent brightener and pigments, may be mixed together initially, usually over a period of from 1 to 10 minutes, preferably from 3 to 7 minutes, and then the silicate may he added slowly, preferably as an aqueous solution of from 205( to 50%, preferably from . 35% to 41%, e.g. 40%,solids content, the addition being effected over a period of from about 2 to about 10 minutes, usually from 3 to 7 minutes. By varying mixing techniques, changing mixer speeds, degree of shear, temperature, etc., the viscosity of the mix . may often be maintained in a workable range, but if the mix becomes excessively viscous it may be thinned.

After completion of crutching the crutcher mix is atomized, preferably by being forced through a nozzle of circular cross-section of internal diameter in the . range from 0.5 mm to 2 mm, at a pressure in the range from 10 to 50 kg/cm^ gauge, into a spray tower, preferably a countercurrent spray tower, in which the drying air is at a temperature in the range from 150° to 350°C. The conditions therein (temperature, spray . droplet size, air flow, holdup time) may be regulated so that the desired extent of decomposition of bicarbonate to carbonate, usually 10% to 70%, preferably 20% to 50%, is obtained. The product leaving the tower is of spherical particles substantially in the 4 to 120 or 140 . mesh range, of a moisture content of from 2.5% to 15%, 472S3 and is screened to be substantially all within such range or a narrower range, e.g. from 4 to 100 or 8 to 100 mesh.

After production of the base particles, when . they contain no silicate, a particulate solid silicate such as hydrous sodium silicate, preferably of the Britesil type mentioned above, of a 1:2 or 1:2.4 NagO^iOg ratio and 20% to 24% moisture content (although 10% to 40% is also feasible) may be mixed with the . base beads in an inclined drum or other mixing and/or tumbling device, normally over a period of from 1 to 5 minutes, and nonionic detergent, in liquid state and at a temperature in the range from 20° to 70°C (room temperature is preferred for normally liquid nonionic . detergents), preferably 20° to 60°C, is sprayed onto . the tumbling surfaces of the base beads (which had been pre-mixed with post-added particulate silicate), The atomized globules of nonionic detergent may he of any suitable size but normally are in the 0.05 mm to . 2 mm diameter range, preferably 0.1mm to 1mm, e.g. 0.1mm to 0.5mm,diameter. Application of the nonionic detergent to the tumbling particles normally takes place over a period of from 1 to 20 minutes, preferably from 2 to 10 minutes, and preferably is by spraying, as . described, but other forms of mixing and admixing may he used too, such as liquid addition to a fluidized bed of the base particles. After completion of addition of the nonionic detergent, other materials to be postadded, such as perfume and proteolytic enzyme, may be . applied.

The alkali metal (sodium or potassium being preferred) carbonates and bicarbonates, most preferably the sodium salts, will be essentially anhydrous in preferred embodiments of the invention but partially hydrated builder salts of this type may he tolerated. Normally, moisture contents will be less than 9%, preferably less than 7%. The mixed product is preferably made by a method which results in a substantial content, e.g. from 10% to 90% of Wegscheider’s salt, any balance being of carbonate 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, should it be desired to apply such to. the product.

In the manufacture of some preferred starting carbonate-bicarbonate mix particles the method of U.S. patent 3,944,500 may be employed and the product thereof, identified as Snowlite obtainable from Allied Chemical Corporation, U.S.A., is preferably used. A typical analysis for Snowlite I is 55% sodium carbonate, 58.5% sodium bicarbonate and 6.5% water, whereas that for another such product, Snowlite II is 30.0%, 66.5% and 3-5%, respectively. Screen analyses (percentages on 10, 40, and 100 mesh screens) are 0.2, 67.6, 96.9 and 99-0, ana 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 is especially low for Snowlite I (2.5% by Allied Chemical Corp. . test Na 17-35) so it is preferred in some instances.

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 method of the said U.S. patent, providing that they are stable . and do not adversely react or interfere with the making of the carbonate-bicarbonate particles. 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, and . vzhen such other adjuvants are present, from 5% to 15% of sodium silicate and/or from 0.1% to 5% of fluorescent brightener and/or from 0.2% to 1.5% of anti-redeposition agent, sometimes with additional water too, to bring the water content of the products within the ranges . previously mentioned. Although the method of the said U.S. patent is a preferable one, the mixed carbonatebicarbonate beads may be made by other techniques, providing that the end product is essentially the same.

The other detergent composition components may be the . same as previously described.

The proportions of bicarbonate-carbonate particles and nonionic detergent in the compositions of the present invention should be chosen to result in the composition being of satisfactory cleaning power and the particles . being free flowing and of desired high bulk density. Preferably the proportion of nonionic detergent to the total of alkali metal bicarbonate and alkali metal carbonate is in the range from 1:2.5 to 1:4.

Such proportions are normally within the range from 15$ to 22% or 25% of nonionic detergent, the balance being mixed bicarbonate-carbonate beads, auxiliary builders, such as silicate (alkali metal silicate) . e.g. sodium silicate, adjuvants and moisture. Preferably, the alkali metal bicarbonate component, sodium bicarbonate, in Wegscheiderite or otherwise, is from 30% to 45%, more preferably from 30% to 4Q%, the carbonate content, in Wegscheiderite or otherwise, . is preferably 15% to 30%, more preferably from 15% to 25%, the moisture content is preferably from 1% to 7%, more preferably from 1% to 5%, the silicate content is from 5% to 15%, preferably from 8% to 12% and the total of adjuvants is from 3% to 10%, preferably from . 4% to 8%, A specifically preferred formulation includes, approximately 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 105°C oven for 5 minutes, but normally excludes the water of hydration of the hydrous sodium silicate.

The manufacturing methods, including post-spraying techniques are essentially the same as those previously . described for treating the spray dried bases and the product characteristics are also similar.

The following Examples illustrate the invention. EXAMPLE 1 Percent . *I1eodol 23-6.5 20.0 Sodium bicarbonate Sodium carbonate •Sodium silicate (Ka^OcSiO^ = 1:2.4) Tinopal 5BM fluorescent brightener - Proteolytic enzyme (Protease) Ultramarine Blue pigment Perfume Water (deionized) 51.0 31.0 .0 2.0 1.5 0.2 0.3 4.0 100.0 . * Condensation product of a higher fatty alcohol of an average of 12 to 13 carbon atoms with about 6.5 mols of ethylene oxide/mol of fatty alcohol.

A. free flowing, high bulk density particulate detergent composition is prepared of the above formula . and is of essentially spherical or globular particles, 99$ of which are of sizes (usually considered as of diameters or effective diameters) in the range from 8 to 100 mesh. The product has a hulk density of Ο.67 g/ml and flows at a rate of about 75$ of that of dry . sand of similar particle sizes, the standard for comparison. It is an excellent heavy duty synthetic organic detergent composition, useful for both hot and cold water washing of both synthetic and natural fibre textiles and it does not leave objectionable . residues on such textiles nor make them boardy ss is sometimes observed after the washing of laundry with detergents containing comparatively high percentages of sodium carbonate.. The product is non-sifting, does not become unacceptably tacky on prolonged storage . at ordinary shelf conditions and remains free flowing and of high density during such storage.

The detergent composition of this Example is made by admixing in a synthetic detergent or soap crutcher, at a temperature of 60°C (the water is . initially pre-heated and heat on the crutcher is maintained to reach and hold such temperature), sodium carbonate and sodium bicarbonate plus stable adjuvants, such as pigment and brightener. The parts by weight employed are 40 of sodiun bicarbonate, 22 of sodium . carbonate, 0.2 of the pigment, 2 of the brightener and 59 of deionized water. Alternatively, city water of low hardness, less than 50 p.p.m., as calcium carbonate, may be substituted for the deionized water in some cases. After from about 5 to about 10 minutes . of mixing, there are added to the crutcher mix 25 parts of 405= solids aqueous sodium silicate solution. Although the mixture tends to become somewhat viscous during the blending operation, by increasing the mixer speed during the addition of the sodium silicate and by . regulating the speed of addition, the viscosity of the mix is held to a level wherein mixing is still obtained and formation of gelled material is minimised. Usually only about 5 or 6 minutes will be taken for blending in the sodium silicate with the other components of the - crutcher mix.

The crutcher mix is then spray dried in a conventional countercurrent spray tower, which is about 10 metres high and 3 metres in diameter, by pumping it at a pressure ο of about 25 kg/cm gauge through an orifice about 1 ma 30. in diameter into drying air (at a temperature of about 300°C inlet and. about 110°C outlet) so as to produce a product essentially of, or substantially in, the 4 to 120 mesh range, which product is cooled to about room temperature and screened so as to be substantially all . (over 99%) within such range. Alternatively, screening is effected to particle sizes in the narrower 4, 6, or 8 to 100 or 120 mesh ranges. In all such instances the base detergent composition beads made are of a comparatively high bulk density, about 0.55 g/ml, and are . free flowing, such flow being about 80% or more of that of comparably sized dry sand.

Onto the base beads, moving in an inclined drum blender so as continuously to present new surfaces, are sprayed 20 parts of the Neodol 25-6.5 in liquid . state at room temperature (25°C). The particles onto which the Neodol 23-6.5 is sprayed as a mist, with droplet diameters of about 1 mm, are initially at a temperature of about 25°C but this may he.increased and the temperature of the Neodol 23-6.5 may also be . increased, usually to about 35° io 45°C, so as to promote rapid penetration of the detergent into the · interiors of the porous and honeycombed globular particles Such spraying is effected within a period of about 8 minutes, after which perfume is applied to the beads . (by spraying) and a proteolytic enzyme powder, of a particle size between 60 and 100 mesh, is dusted onto the surfaces of the particles still in the mixing drum, each of which procedures takes about 3 minutes. The beads are then cooled to room temperature or slightly . above, but to not more than 30°C, so as to avoid un20 necessary loss of volatile perfume components by evaporation.

The finished product, screened to 4 to 120 (or 8 to 100) mesh size, is of the desired high bulk density . and very good flow characteristics and is ''bottled, packed and stored in a warehouse, ready for shipment.

When tested after storage it is found to be a satisfactory household laundry detergent, useful for washing in both hot and cold water, and suprisingly, . leaves little or no residue of carbonate on washed materials and does not make them boardy. The product remains free flowing during storage. It does not cake objectionably nor does it develop lazy flow characteristics on storage. The pH of a 0.07% solution thereof . in wash water is about 9.5, an ideal pH for proteolytic enzymatic action, which assists the detergent composition In cleaning and removing stains from washed fabrics, whether of synthetic (e.g. nylon, polyester and permanent pressure natural-synthetic blends) or . natural fabrics (e.g. cottons).

The described product is significantly superior to a number of other detergent compositions in which the carbonate: bicarbonate ratios are outside the ranges previously described. Thus, when instead of a 1:1 ratio . of carbonate to bicarbonate, by weight, that ratio is. increased to 3:1, with the total carbonate plus bicarbonate content being constant, the cleaning power of the composition in a standard test at 0.07% product concentration, using wash water of 150 p.p.m. hardness, , as calcium carbonate (mixed magnesium and calcium hardness in 2:3 ratio) in the washing of test fabrics soiled, with a standard soil, while better than that for an all-carbonate-built detergent composition, is significantly inferior to that of compositions of the present invention . in which the sane total of carbonate and bicarbonate is employed an in which the ratios of carbonate to carbonate are 2:1, 1:1 and 1:3· Such results obtain when washing is in hot water (49°C) and in cold water (21 °C), but the improvements in cleaning power are . greater in hot water washing. Thus, when the carbonate content is 60% and there is no bicarbonate in the product (originally none was added in the crutcher or all the bicarbonate that was added decomposed to carbonate), if the soil removal noted is taken as a base, . then at 45% sodium carbonate and 155= sodium bicarbonate (with all the other components still present) increases of 6.8 cleaning units after the washing of test fabrics at 49°C and 1.3 units at 21 °C are obtained; at 405= and 20%, respectively, such readings are +9.7 and . =-2.3; at 30/0 and 30%, respectively, they are +14.1 and +5·5; at 15 and 45%, respectively, they are +13.1 and. +2.0 and at 0 and 60%, respectively, they are +3.9 and +1.0.

In a variation of the above experiment, when . silicate is omitted from the crutcher it is post-added as hydrous sodium silicate (3ritesil H-20, containing 20% of water) before the addition of the nonionic detergent (preferred), after addition of the nonionic detergent or part before and part after The products obtained . are also good home laundry detergents of high bulk density and are sufficiently free flowing to be commercially acceptable. In those cases where the percentage of silicate desired to be utilized in the formulation is greater than 15% and, sometimes, greater than 10%, . at least part of the silicate will often be post-added, due at least in part to problems of increased viscosity of the crutcher mix containing the larger proportions of silicate.

Although it is preferred to post-add the nonionic . detergent to the beads shortly after manufacture and also to post-add any other components of the product not in the spray dried base beads, this can also be done after aging of the base beads for periods from 20 minutes to several days without loss of their absorbing powers.

. In such cases it may be desirable to heat the beads before application of the nonionic detergent but by proper choice of nonionic detergent type, with respect to melting point, this is avoidable.

In a modification of the above described example, . instead of employing sodiun carbonate and sodium bi- . carbonate powders as a charge to the crutcher, sodium, sesquicarbonate and Vegscheider’s salt are used, supplementing sodium carbonate being added when Wegscheider’s salt Is employed and sodium bicarbonate being . added when sodium sesquicarbonate is utilized. Also, the water of hydration In the sodium sesquicarbonate is taken into account in computing the amount of deionized water to be admixed with the carbonate and bicarbonate and other adjuvants in the crutcher. Thus, instead of . charging 40 parts of sodium bicarbonate and 22 parts of 47363 sodiun carbonate, when. Wegscheider1s salt is used the charge will be of 53-3 parts of Wegscheider's salt and 8.7 parts of sodium carbonate (59 parts of deionised water), and when sodium sesquicarbonate is used such . charge will be 52.3 parts of sodium sesquicarbonate (including 8.3 parts of water of hydration) and 18 parts of sodium bicarbonate and the water to be added to the crutcher will be decreased from 59 to 50.7 parts. The products made by utilizing such different starting . materials are of the same characteristics as those previously described and are made by the same methods, after charging of the crutcher.

Although silicate, enzyme, fluorescent brightener, pigment and perfume are desired components of the present , compositions (and various other adjuvants, such as those previously mentioned, may also be present), they are not essential to the production of a usefully detersive product. Thus, when they are omitted the beads made by spray drying of a described crutcher mix under conditions . mentioned are of essentially the same characteristics, even slightly more porous, and by spraying into them .of nonioric detergent they may be converted to a useful laundry detergent product. However, the product containing silicate possesses greater bead strength and · is better suited to commercial use. In place of the silicate, a phosphate-free, silicate-free product may have included therein filler salts or other builder salts, such as sodium sulphate, sodium chloride or borax or other such materials and, optionally, in some cases, . additional quantities, up to the 30% previously mentioned for the sodium perborate content of the bleaching detergent, may be present When such larger proportions are present the proportions of other components will be decreased correspondingly. The products still have . the desired characteristics previously reported.

EXAMPLE 2 Products of the formula given in Exanple 1 are made by utilizing different initial proportions of sodium carbonate and sodium bicarbonate and modifying . the drying tower conditions so as to cause more or less decomposition of sodium bicarbonate, e.g. from 10% to 70%. For example, instead of employing 40 parts of sodium bicarbonate and 22 parts of sodium carbonate, such parts may be changed to 45 and 17; 50 and 12; . 55 and 27 or intermediate proportions, while tower conditions (temperatures, hold-up time) are changed to increase or diminish decomposition of the bicarbonate. The finished products are of essentially the same properties as those of the preferred embodiment of the . invention described in Exanple 1.

EXAMPLE 3 Percent Nonionic detergent (condensation product of higher fatty alcohol of an average . . of 12-13 carbon atoms with polyethylene oxide of 6 to 7 nols of ethylene oxide per mol of higher fatty alcohol) Mixed sodium bicarbonate-sodium carbonate builder containing 66.5% sodium bicarbonate, 30$ sodium carbonate and 3.5$ water, including at least 10$ Wegscheiderite Hydrous sodium silicate (Ka20:Si02 - 1:2, . containing 18$ HgO) Fluorescent brightener Sodium carboxymethylcellulose Proteolytic enzyme Ultramarine Blue Perfume 65.0 .0 2.0 1.0 1.5 0.2 0.3 100.0 a Neodol 2306.5 b Snowlite II c 3ritesil H20 . d Tinopal 5BH e *Alcalass, manufactured by Novo Industries, Inc.

The mixed . sodium bicarbonate-sodium carbonate builder particles, of particle sizes previously described, and containing about 20$ Vegscheiderite, together with . sodium bicarbonate and sodium- carbonate, are charged, at room temperature (25°C), 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 hydro-s 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 range. However, in other experiments the particulate adjuvants, except . for the pigments, are in ths 4 to 100 mesh range too, and *Alcalase is a Trade Mark. similar results are obtainable.

After pre-mixing the various particulate solid components of the product over a period of from one to three minutes the nonionic detergent is sprayed . onto the moving surfaces of the particles over a period of about 3 minutes, after which mixing in the drum is continued for another 5 minutes. The nonionic spray is in the form of droplets largely in the range of 0.05 mm to 0.1 mm and is at a temperature of 25°C, . sufficient 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 flow rate 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 . 3 months* storage under average ambient conditions the composition pours readily and the bulk density is' found still to be about 0.7 g/ml.

When subjected to property evaluation and washing tests or practical laundry tests it is found that the · ccmposition is non-dusting, free flowing, non-caking and of acceptable detergency for commercial applications, comparing favourably to tripolyphosphate-built productsof similar active ingredient contents. The carbonate does not produce excess alkalinity, due to the presence . of the bicarbonate, which buffers the carbonate and 472S3 results in a v/ash water having a pH of about 9.5 at both 0.07% and 0.15% product concentrations. Also, because of the comparatively low content of carbonate the product is safe for commercial marketing and is . not considered to be intolerably hazardous when accidentally ingested hy 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 hy 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 nixing drum previously described, over a period oi about . 3 minutes, ΐ/ith the drum moving at slow speed, e.g. 10 r.p.m. The product resulting is a useful detergent at the same concentration used for the previous experiment (1/4 cup or about 45g per 65 litre 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 composition. bhen 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 carbonatecontaining 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 50. as the preferred products of the present invention because of its comparatively poor flow characteristics, higher pH ar.d comparative toxicity when accidentally ingested.

EXAMPLE 4 Percent Snowlite I Hydrous sodium silicate (KagOcSiOg = 1:2 70.0 .0 .0 containing 18% HgO) Keodol 25-7 . 100.0 The Snowlite particles are charged at room temperature to the inclined drum of Exanple 3 or to comparable twin shell, V-or Patterson-Kelley blenders, the hydrous silicate, desirably of approximately ths sane . particle size, is added to the drum, while mixing, over a period of about 2 minutes and nixing is continued for another minute to blend the silicate evenly with the carbonate-bicarbonate particles. Then, over a period of another 5 minutes the nonionic detergent, . at a temperature of about 30°C, is sprayed onto the moving surfaces of the particles. The product resulting is an excellent concentrated heavy duty, non-phosphate detergent composition, useful for washing of laundry at a concentration of from 0.05% to 0.2% in the wash water . (0.07% and 0.15% are most frequently employed in toploading 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% of that of sand of similar particle size. Such a flow rate is . superior to that of most of the spray dried heavy duty , 47263 detergent compositions commercially marketed today. Comparable products are made utilizing Neodol 45-11 and Alfonic 1618-65 instead of Neodol 25-7 but such nonionics are raised to elevated temperatures, e.g. . 45°C, to promote penetrations into the interiors of the base particles, for reasons previously stated.

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 composition of acceptable flow, bulk density and storage properties for various applications.

EXAMPLE 5 · Percent Snowlite I 35-0 Snowlite II 35.0 Neodol 23-6.5 20.0 Hydrous sodium silicate 10.0 . (as in Examples 3 and 4) « _ 100.0 The manufacturing procedure of Example 4 is followed except that the two different Snowlite materials are pre-blended over a period of about 2 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).

EXAMPLE 6 The compositions of the products of the previous . examples are varied +10%, +20% and +30%, within the ranges given and similarly, the procedures are varied v/ith respect to times and temperatures. The products made are within the rangesfor flow characteristics, bulk density and particle size and are of satisfactory detersive properties for their intended uses.

Claims (13)

1. A free flowing phosphate-free particulate detergent composition suitable for heavy duty laundering, of a bulk density of at least 0.6 g/ml and particle sizes in the 4 to 120 mesh range which comprises spray dried 5. particles of alkali metal carbonate and alkali metal bicarbonate containing a normally liquid or pasty nonionic detergent introduced after the spray drying.

2. A detergent composition according to Claim 1 wherein each of the spray dried particles of alkali metal carbonate and 10 alkali metal bicarbonate includes both alkali metal carbonate and alkali metal bicarbonate; the weight ratio of alkali metal carbonate to alkali metal bicarbonate is in the range from 2:1 to 1:5; the nonionic detergent is a higher fatty alcohol-polyethylene 15 oxide condensate wherein the higher fatty alcohol is of 10 to 18 carbon atoms and the polyethylene oxide is of 3 to 20 mols of ethylene oxide per mol of higher fatty alcohol; the percentages of mixed alkali metal carbonate and alkali metal bicarbonate and of non20 ionic detergent are in the ranges from 40% to 90% and from 10% to 30%, respectively; and any balance is of auxiliary builder(s), adjuvants and water.

3. A detergent composition according to Claim 2 wherein the alkali metal carbonate is sodium carbonate, 25 the alkali metal bicarbonate is sodium bicarbonate, the particles of mixed sodium carbonate and sodium bicarbonate are those obtained by spray drying an 4. *7263 aqueous crutcher mix of such materials higher in proportion of sodium bicarbonate to sodium carbonate than in the spray dried particles, the weight ratio of NagCO^:NaHCO^ in the particles is in the range 5. from 1:0.8 to 1:3. such mixture of sodium carbonate and sodium bicarbonate is in each particle, and the proportions of combined sodium carbonate and sodium bicarbonate and of nonionic detergent are in the ranges from 50% to 70% and from 15% to 25%, 10. respectively.

4. A detergent composition according to Claim 3 wherein the nonionic detergent is a condensation product of a higher fatty alcohol of an average of 12 to 13 carbon atoms and about 6.5 mols of ethylene 15. oxide per mol of higher fatty alcohol and which comprises about 20% of such nonionic detergent, about 31% of sodium bicarbonate, about 31% of sodium carbonate, about 10% of sodium silicate of Na 2 0:Si0 2 ratio of about 1:2.4, about 2% of water and about 4% of 20. adjuvants, and which is of a bulk density of about 0.7 g/ml.

5. A detergent composition according to Claim 1 of a moisture content below 10% and particle sizes in the 4 to 100 mesh range in which the proportion 25. of carbonate to bicarbonate is in the range from 1 : 0.8 to 1 : 3 ? the percentage of normally liquid or pasty nonionic detergent is from 15%> to 22% and the proportion of nonionic detergent to the total of alkali metal bicarbonate and alkali metal carbonate 3Q. is in the range from 1:2.5 to 1:4.

6. A detergent composition according to Claim 5 wherein the mixture of alkali metal bicarbonate and alkali metal carbonate is a mixture of sodium bicarbonate and sodium carbonate containing at least 5. 10% of Wegscheider's salt, and 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 10. fatty alcohol, in such proportions that the percentage of sodium bicarbonate including that in Wegscheider 1 s salt, is in xhe range from 30% to 45% and that of sodium carbonate, including that in Wegscheider’s salt, is in the range from 15% to 30%, and which includes 15. from 5% to 15% of hydrous sodium silicate of Na^OsSiOg ratio of about 1:2, from 3% to 10% of adjuvants and from 1% to 7% of moisture.

7. A detergent composition according to Claim 6 which has a flow rate about 80% of that of similarly 2o sized dry 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 an average of 12 to 13 carbon atoms and about 6.5 mols of ethylene oxide per mol of higher fatty alcohol, the mixture of 25. sodium bicarbonate and sodium carbonate is one containing about 30% of sodium carbonate, 66.5% of sodium bicarbonate and 3-5% of moisture, and the hydrous sodium silicate includes about 18% of water, and which comprises about 20% of the nonionic 30. detergent, about 65% of the mixture of sodium bicarbonate, sodium carbonate and water, including 4 7 2 63 at least 10% of Vegscheider's salt, about 10% of hydrous sodium silicate and about 5% of adjuvants,

8. A method of making a free flowing phosphatefree particulate detergent composition suitable for 5. heavy duty laundering, of a bulk density of at least 0.6 g/ml and comprising alkali metal carbonate, alkali metal bicarbonate and nonionic detergent; which method comprises spray drying an aqueous crutcher mix of alkali metal bicarbonate to produce 10. beads of such alkali bicarbonate mixed with alkali metal carbonate decomposition product thereof, of a particle size in the 4 to 120 mesh range, and applying to the particles a normally liquid or pasty nonionic detergent, in liquid state, so as to 15. cause the detergent to penetrate into interiors of the particles and increase their bulk density.

9. A method according to Claim 8 wherein some alkali metal carbonate is in the crutcher mix to be sprayed, spray drying is controlled so that the 20 weight ratio of alkali metal carbonate to alkali metal bicarbonate in the spray dried beads is in the range from 2:1 to 1:5, the nonionic detergent is a higher fatty alcohol-polyethylene oxide condensate wherein the higher fatty alcohol is of 10 to 18 25. carbon atoms and the polyethylene oxide is of 3 to 20 mols of ethylene oxide per mol of higher fatty alcohol, the nonionic detergent, in liquid state, is sprayed onto moving surfaces of the alkali metal carbonate - alkali metal bicarbonate spray dried 3Q. beads, and percentages of mixed alkali metal carbonate and alkali metal bicarbonate and nonionic detergent in the laundry detergent are in the range from 40% to 90% and from 10% to 30%, respectively, any balance being auxiliary builders, adjuvants and 5 water. 10. A method according to Claim 9 wherein the alkali metal carbonate is sodium carbonate and the alkali metal bicarbonate is sodium bicarbonate, the spray drying is of a crutcher mix of about 50% solids

10. content, of which solids at least 80% are of sodium carbonate and sodium bicarbonate and the quantities of such carbonate and bicarbonate are about equal, the nonionic detergent is a condensation product of a higher fatty alcohol of an average of 12 to 13 15. carbon atoms per mol and a polyethylene oxide of about 6.5 ethylene oxide groups per mol of higher fatty alcohol and the nonionic detergent is sprayed as a spray of droplets of sizes in the 0.1 mm to 0.5 mm diameter range onto the moving surfaces of 20. sodium carbonate - sodium bicarbonate spray dried beads of particle sizes in the 4 to 120 mesh range, which are at a moisture content of from 2.5% to 15%, in a moving bed.

11. A method according to Claim 8 which is 25, substantially as described in any of the Examples,

12. A free flowing phosphate-free particulate detergent composition suitable for heavy duty laundering which has been made by a method according to any of Claims 8 to 11.

13. A detergent composition according to Claim 1 and having a formulation substantially as described in any of the Examples.