CA1069013A

CA1069013A - Production of detergent compositions

Info

Publication number: CA1069013A
Application number: CA235,127A
Authority: CA
Inventors: Robert W. Anderson; Michael Curtis; Terence F. Child
Original assignee: Unilever PLC
Current assignee: Unilever PLC
Priority date: 1974-09-06
Filing date: 1975-09-05
Publication date: 1980-01-01
Also published as: BE832964A; IT1047163B; SE418407B; SE7509918L; FR2288779A1; GB1515273A; JPS5910400B2; IN145380B; FR2288144A1; FR2288779B1; JPS5152404A; NL7510271A; FR2288144B1; DE2539429C2; ATA687975A; CH619488A5; AT363156B; DE2539429A1

Abstract

ABSTRACT OF THE DISCLOSURE
Detergent compositions based on alkali metal carbonate detergency builders and containing finely divided calcium carbonate having a surface area of at least about 5 m2/g, are prepared by admixing a base powder comprising a detergent active compound and optionally at least some of the alkali metal carbonate with granules formed of the finely divided calcium carbonate and a binding agent. Granules of finely divident calcium carbonate are provided which comprise 25% to 99.5% by weight of calcium carbonate with a binding agent and which have a bulk density of 0.16 to 0.96 gm/cc.

Description

cC.761a The present invention relates to the production oL
detergent compositions, and in particular to the production of particulate detergent compositions which are intended for fabric washing.
Fabric washing detergent compositions co~monly incorporate as the major ingredients one or more detergent active compounds and a so-called detergency builder.
Conventional detergency builders are co~monly inorganic materials, particularly the condensed phosphates, for example sodium tripolyphospbate. It has, however, been suggested that the use of these phosphate detergency builders can contribute -to eutrophication problems. Alternative detergency `~ builders which have been proposed 3 for example sodium nitrilotriacetate ~N~A) and synthetic polymeric polyelectrolyte .:~ 15 ~aterials, tend to be more egpensive or less efficient than ,i the phosphate detergency builders, or otherwise unsatisfactory :
for one reason or another.
- It is known that sodium carbonate can function as a detergency builder by removing the calcium from hard water in the form of precipitated calcium carbonate. But such calcium carbonate tends to accumulate on washing machine surfaces and on washed fabrics, and this can lead to fabric harshness.
In the specification of our Canadian patent i application No.179,072 , we have described detergent compositions which are based on an alkali metal carbonate detergency builder together with finely divided calcium carbonate, in addition to a detergent aotive compound or compounds. These compositions tend to form less inorganic deposits on washed fabrics, and hence deorease the fabric harshne~s which is normally a disadvantage of alkali metal ' ":

cC.7fila carbonate detergency builders. ~his is apparently becau~e the precipitated calcium carbonate is deposited on -the added calcium carbonate instead of on the fabrics or washing machine surfaces.
Moreover, by encouraging the calcium hardness in the wash water to be removed from solution in this way the detergencies of the compositions are improved compared with those compositions in which inorganic deposition on the fabrics is decreased by inhibition of the precipitation process, either by the addition oi anti-deposition agents or by the action of precipitatiorl inhibitors which we have found to be present in wash liquors. The added calcium carbonate also appears to act as a scavenger for the calcium carbonate precipitation inhibitors. ~hi9 action facilitates the nucle~tion process and further encourages removal of calcium hardness from the wa~h liquor.
Those detergent ~ompo~itions based on an alkali metal carbonate detergency builder and ~inely divided calcium carbonate can be made by simple admixture of the ingredients.
~owever, this can give rise to problems of segregation of the ingredients due to different particle si~es and densities, besides dust problems in the mixing processes. Spray drying can also be used,as is common practice for making most conventional fabric washing detergent powders, but this can give rise to problems due to the interaction between certain ingredients, especially with the finely divided calcium carbonate the efficiency of which can be severely diminisbed by other ingredients present in the composition.
According to the present invention a detergent composition compri~ing a detergent active ~ompound, an alkali cC.761a :~69~)13 metal carbonate detergency builder and finely divided calcium carbonate,is prepared by admixture of a detergent base powder and granules formed from the finely divided calcium carbonate.
With suitable selection of base powder and granule physical properties, the resultant compositions do not suffer from the usual problems described above for simple dry mixed products, and some reduction in the evaporative load may be achieved by not including the bulky calcium carbonate ln the slurry for conventional spray drying. Moreover, the storage properties of the resultant detergent composition are improved by using the process described. But, most importantly, the full activity of the calcium carbonate can be maintained by the selection of the optimum granulation conditions and the use of preferred additives in the granulation prooess according lS to -the invention.
The detergent compositions can be formed using any granules of calcium carbonate which are suitable for detergents use, that is in having appropriate particle sizes and bulk densities. The granules must also be readily dispersible in water, which is achieved by using a water soluble or dispersible binding agent for the calcium carbonate granules.
The granulation of calcium carbonate has baen proposed hitherto for uses other than in detergent compositions, for example for agricultural purposes or as a pigment in the ceramic, paint or rubber industries. However, the granules for these purposes have tended to be poorly dispersible in water and of inappropriate size or density or otherwise unsuitable for detergents u~e.
:~ The invention provides granules of finely divided ~ 30 calcium carbonate which are suitable for detergents use and .~

`` ` lOG9l)13 cc . 761a also a preferred process for making sueh granules using finely divided calcium carbonate wbich has never been dried.
The granules according to the invention contain from about 25% to about 99 . 5% by weight of the calcium carbonate and 5 from 0. 5% to 75% by weight of a binding agent, and they have a bulk density of from about 0.16 to about 0.96 gm/cc.
- The calciu~ carbonate used to form the granules should be finely divided, and should have a specific surface area of at least ~bout 5 s~uare mètres per gram (m2/g), generally at least 10 about 10 m2/g, and preferably at least about 20 m2/g. The particularly preferred calcium carbonate has a specific sur~ace area of from about 30 to a~out lO0 m2/g~ especially about 50 to ahout 85 m2/g. Calcium carbonates with specific surface areasin excess of about 100 m2/g could be used, up to say about 150 m2/g, if such materials are economically available, but it appears to be unlikely that any highar surface areas will be achievable commercially and this may in any case be undesirable for other reasons, for example especially small particles, ie with very high specific surface areas, may 20 have a tendenoy to dissolve during the washing process and there may be dust problems when forming the granules.
Surface areas of the calcium carbonate are determined by the standard Brunauer, Emmet and Teller (BET ) method, using an AREA-meter made by $tr~hlein & Co., and operated acoording 25 to the suppliers' instruction manual. The procedure for degassing the samples under investigation is usually left to : the operator, but we have found that a degassing procedure in which the s~mples are heated for 2 hours at 175C under a stream of dry nitrogen is effective to give repeatable results. Somewhat higher apparent surface areas may sometimes /---.. ~ , .

~C . 761a 93)~3 be obtained by dega~sing at lower te~peratures under vacuum but this procedure i9 more time consuming and le~s convenieut.
As an indication o~ the g~neral relat~on~hip between particle size and sur~ace area, we have found that calcite with a surface area of about 50 m2/g has an average primary crystal size (diameter) of about 250 Angstrom ~R), whilst i~
the primary crystal size is decreased to about 150 ~ the surface area increases to about 80 m2/g. In practice some aggregation of the primary crystals generally takes place to form larger particles, irrespective of the ~ranulation process But it is desirable that the aggregated particle size of the calcium carbonate should be fairly uniform, and in particular that there should be no appreciable quantity of larger particles, eg over about 15 /u, which after - 15 dispersion of the granules could easily get trapped in the fabrics being washed or possibly cause abrasive damage to washing machine parts, Any crystalline form of calcium carbonate may be used, but calcite is preferred, as aragonite and vaterite appear to be more difficult to prepare with high sur~ace areas, and it appears that calcite is a little less soluble than aragonite or vaterite at most usual wash temper~tures. When any aragonite or vaterite is used it is generally in admixture with calcite. Suitable forms of calcium carbonate, especially calcite, are commercially available. The calciwm carbonate is preferably in substantially pure form, but this is not essential and the calcium carbonate used may contain minor amounts of other cations with or without other anions or water mo7ecules.
Finely divided calcium carbonate can be prepared ,. ~.'.' cC.7~1~
`' ~i9~i~3 conveniently by precipitation processes, ~or example by passing carbon dioxide into a suspen~ion of calcium - hydroxide. In this case it may be c~nvenient to use the resultant aqueous slurry oi calcium carbonate when preparing the granules, as drying the calcium carbonate may tend to encourage aggregation of the calcium carbonate particles which decreases their efficiency. Other chemical precipitation reactions may be employed to produce the calciu~ carbonate, especially the reaction between any su~ficiently soluble calcium and carbonate salts, for example by réaction between calcium sulphate or calcium hydroxide and sodium carbonate, but these reactions fQrm a~ueous slurries containing undesired dissolved salts, ie ~odium sulphate and sodium hydroxide in the example3 mentioned. ~his means that the calcium carbonate ~; 15 would have to be filtered from the slurry before use unless the dissolved salts could be tolerated in the granules and subsequently in the detergent compositions.
It should be mentioned that the calcium carbonate may be adsorbed onto a substrate, for example when it i9 formed by precipitation, in which case it may not be possible to measure accurately ths surface area of the calcium carbo~ate alone. The effective surface area can then be calculated by checking the effectiveness oi the calcium carbonate and relating thi~ to the ef~ectiveness of calcium carbonates o~
known surface areas. Alternatively, it may be possible to use electron microscopy to determine the average particle size, from which an indication of surface area might be obtained, but this should be checked ~y determining $he effectiveness of the calcium carbonate in use.
Finely divided calcium carbonate may also be prepared by grinding mineral3 such as limestone or chalk, but this _ 7 _ /---~ .

~ 1069Vi3 cc .76ia is not readily e~fec~tive as it is dif~icul-t to ob-tain a high-enough sur~ace area.
Granulation of -the calcium carbonate may be accomplished by any conventional granulation process in which the finely divided calcium carbonate particles are bound together. If desired, water or an organic solvent may be present during granulation, with the subsequent evaporation of some or all of the water or solvent, if desired, eg by the application of heat. When starting from powdered calcium carbonate, -the most convenient methods of granulation are those in which a solution or dispersion of the binding agent is mixed with or sprayed onto the calcium carbonate, ~or example in a planetary mixer, an inclined pan, a drum or a fludised bed, until granules of the desired size are formed. Alternatively, the calcium lS carbonate and binding agent may be formed into granules in an extrusion process to form so-called noodles or ribbon. In a further granulation process the calcium carbonate and binding agent are sprayed together into a gas stream to form granular droplets, with or without the evaporation of water or a solvent, this process being particularly convenient when the calcium carbonate is supplied in aqueous dispersion. It is also possible to form the granules by coating a detergent base powder with a calci~ carbonate dispersion and then drying the granules, instead of forming the granules separately for subsequent admixture with -the detergent base powder.
In any of the granulation processes heat may be applied if desired, provided of course that temperatures are not so high that the calcium carbonate or any binding agent present are decomposed or that the granules are unduly hardened or embrittled or otherwise made unsuitable for use ~g~3 cc . 761a in detergent composi-tiorls. Such hea-t may be applied externally or by chemical reaction, eg by the heat of hydration of some binding agents such as sodium carbonate which may take up wa-ter from the calcium carbonate slurry.
The amount of calcium carbonate in the granules may vary widely from a minimum level of about 2S% up to a maximum of about 99.5% calcium carbonate if a low level of only about 0.5% binding agent is employed. Lower levels of calcium carbonate are appropriate when the binding agent is also a detergent ingredient, or when the granules con-tain detergent ingredients in addition to the calcium carbonate and a binding agent. The optimum level depends on many iactors including the type of calcium carbonate and the amounts of calcium carbonate and other ingredients desired in the final detergent 15 composition, and on the form in which the calcium carbonate is supplied and the process for making the granules. In accordance with the invention granules can be made with more than 60% by weight of calcium carbonate, for example from about 75% to about 95% by weight of the granule. Eowever, the problems of granule friability tend to become more difficult at higher calcium carbonate levels.
The binding agent may be any water soluble or dispersible material or mixture of materials which is capable of binding together the calcium carbonate particles in the granules, but which when the granules are dispersed in water will facilitate disintegration of the particles so as to allow the calcium carbonate to disperse in the water and function effectively.
It is of course necessary that the binding agent sbould not have any other deleterious effect on the properties of the detergent compositions in which the granules are used, for ~ g ~

~6~ c c . 761a example it should not be highly toxic, highly coloured or other-wise objectionable, nor shoulcl the hinding agent inhibit the precipitation of calcium carbonate in the reaction be-tween alkali metal carbonate detergency builders and ca]cium ions from hard water. Preferably the binding agent also has a use~ul function in the detergent composition after disintegration of the granules and dispersion of -the calcium carbonate, ~or example it may be a detergent active compound or another conventional deter~ent additive. Specific examples of binding agents are anionic detergent active compounds such as alkyl benzene sulphonates, alkyl sulphates and sulphates of ethoxylated alcohols, fatty alcohol ethoxylate acetates, and olefin sulphonates, fat-ty alkyl ethanolamides, sodium carbonate, sodium silicates, sodium toluene sulphonate, bentonite, sugar esters, sodium carboxymethylcellulose, sodium alginate, gelatin, polyvinylalcohol, dextran sulphates, urea and dextrin.
~ he amount of the binding agent used may be varied widely from about 0. 5% to about 75~, for example from about

2% to about 40%~ by weight of the granules, with larger levels of binding agents being employed when they are also .
useful detergent ingredients. Mixtures of binding agents may be used and also other materials which are not binding agents may be included in the granules, especially low levels of detergent ingredients which are sensitive to heat and cannot therefore be included in base detergent powders made by normal spray drying, for example en~ymes, such aæ proteases and amylases, and some an-ti-redeposition agents.
It should be noted that whilst the binding agents may assist in the formation o~ the granules and subsequently aid the dispersion of the calcium carbonate particles in water, - ~0~

.
., l3 cC.761~

some otherwise suitable binding agents can increase the friability of the granules. This applies particularly to certain anionic detergent compounds which can be used as j binding agents. If such binding agents are used, the granules need to be handled more gently, especially during mixing and transporting the granules prior to packing. On the other hand, certain binding agents such as sodium silicate can be used to form excellent granules o~ low friability, but the dispersibility in water of such granules tends to be decreased. It is necessary therefore to select the amount and type of binding agent or agents to give the desired granule properties having regard to the properties desired in the ~inal detergent composition.
Also, if desired, the granules may include non-substantive dyes or pigments to colour them and thereby impart attractive speckled appearances to detergent composi-tions containing the granules. Generally some residual water is also present in the granules, up to levels as high as about ~0% by weight, particularly if they are prepared from a calcium carbonate slurry or paste rather than from powdered calcium carbonate, -the ~ormer being preferred as this is generally more economical because the step of fully ; drying the calcium carbonate is avoided. ~he use of precipi-tated calcium carbonate which has never been dried is also particularly advantageous as the calcium carbonate itself is then more effective in the final detergent compositions, apparently due to decreased aggregation of the calcium carbonate particles.
~he calcium carbonate granules preferably have a regular shape and size to improve the appearance of the .

.

' cC.761a 6~3 detergent compositions in which they are used. The shape depends of course on the method of manufacture of the granules and tends to be generally spherical if simple granul-ation -techniques are employed, or elongated if extrusion 5 processes are used, though extruded granules may be rounded off by subsequent treatment if desired, for example in a marumariser. If t'he granules are produced by spray drying processes, the granules tend to be less regular in shape and to have a ho:Llow or pitted structure caused by the rapid evaporation of water. The average particle sizes of the granules should generally 'be within the range of from about 0.1 mm to about 2.5 mm, ie for their maximum dimensions, though granules can be larger than this, especially granules of elongated shape which can be up to about 10 mm in length.
lS The calcium carbonate granules preferably have a bulk ` density about the same as that of the detergent base powder, the normal range for which is generally from abouS 10 to about 60 lbs/cu ft, (ie about 0.16 to about 0.96 gm/cc), especially about 15 to 30 lbs/cu ft, (ie about 0.24 to about ,;
0.48 gm/cc), for spray dried powders. But with higher bulk densities, for exa~ple over about 45 lbs/cu ft, (ie about 0.72 gm/cc), the calcite granules may tend to be less dispersible in water and less satisfactory for detergents use.
~he amount of the granules used in the detergent compositions is dependent on the amount of calcium carbonate in the granules and the level of calcium carbonate desired " in the compositions. ~he latter should generally be at least about 5h and preferably at least about 10% up to about 30 60%~ more preferably from about 15% to about ~oo/O by weight, :

~ 69V~3 cc . 761a of the detergent compositions. Within the broad range, th~ lower levels of calcium carbonate may be satis~actory under certain conditions of use and with particularly effective calcium carbonates. Howeverl with less effective calcium carbonates and especially under conditions of use at low product concentration, as for example under typical North - American washing conditions, it is preferred to use higher levels of calcium carbona-te within the preferred range mentioned. The specific surface area of -the calcium carbonate very markedly affects its properties, with high surface area materials being,more effective, so that lower amounts of such materials can be used to good effect in comparison with calcium carbonates of low specific surface area.

- Thus, the amount of calcium carbonate granules added to the base powder to form the detergent compositions should be from about 5% up to a practical maximum of about 80%, and preferably not more than about 60% by weight, which i9 set by the need to retain enough room in the detergent composition for other ingredients in the base powder. It will be a~preciated that if higher levels of calcium carbonate, eg over about 35% by weight, are desired in the detergent compositions, it is necessary to have higher level~, eg over about 75%, of ca]cium carbonate in the granule~.
The calcium carbonate may be formed into the granules from either powder, paste or slurry form. The latter is generally preferred as it avoids the cost of drying the calcium carbonate after its production by precipitation, and the properties of the calcium carbonate also tend to be better if it is not dried before granulation, because drying encourages aggregation of the calcium carbonate particles.

, cC.761a ~3L1969()~
However, if the calcium carbonate is dried be~ore granulation it is possible to treat it~ pr~ferably before drying, wi-th a dispersing aid as described in -the specifications of our copending Canadian patent applications Nos.207~57 and 207,056 . Furthermore, if granulation is accomplished using calcium carbonate slurry, it is desirable to trea-t the calcium carbonate before or during granulation with a dispersi-ng aid. Advantageously the binding agent used is also itself a dispersing aid, or a mixture of binding agents is used with a dispersing aid.
If the calcium carbonate is used in slurry form to make the granules as preferred, it should be at a concentration of not more than about 50% by weight of calcium carbonat0 in the slurry as higher concentrations than this are not readily workable. The maxim-wm workable slurry concentration depends . . _ . .
on the type of calcium carbonate used and its specific surface area and whether or not any viscosity modifiers are present; calcium carbonates of higher specific surface area are usually workable only at lower concentrations, for 2Q example about 30/0 or 40/0 by weight for calcites of surface areas of about 70-80m2/g.
The amounts and types of the alkali metal carbonate used in the detergent compositions with the calcium carbonate granules are the same as described in the specification of our first afore-mentioned patent applications. More specifically, the alkali metal carbonate used i9 preferably sodium or potassium carbonate or a mixture thereof 9 for reasons of cost and efficiency. The carbonate salt is preferably fully neutralised, but it ~ay be partially - 30 neutralised, for example a sesquicarbonate may be used in partial replacement of the normal carbonate salt.

` ~069~13 cc . 761a ~ he amount of the alkali metal carbonate in the deterge~t composition can be varied widely, bu~ the amount should be a-t leas$ about 10% by weight, pre~erably from about 20% to 60% by weight, though an amount of up to about 5 75% could possibly be used if desired in special products.
The amount of the alkali metal carbonate is determined on an anhydrous basis, though the salts may be hydrated either before or when incorporated into the detergent compositions.
It should be mentioned that within the preferred range the higher levels of alkali metal carbonate tend to be required under conditions of use at low product concentrations, as is commonly the practice in North America, and the converse applies under conditions of use at higher product concentrations, as tends to occur in Europe. It should be noted that it may also be desirable to limit the carbonate content to a lower level within the range mentioned, so as to decrease the risk of internal damage following any accidental ingestlon, for ' example by children.
; The alkali metal carbonate may be included in the - 20 detergent base powder or in the calcium carbonate granules, where it can func-tion as a binding agent, either alone or in admixture with another binding agent. Alternatively, the alkali metal carbonate may be included in both the detergent base powder and the calcium carbonate granules. This latter : 25 is preferred, especially if the alkali metal carbonate is used at higher levels of from about 25% to 50% by weight in the composition.
It is also essential to use in the detergent compositions of the present invention one or more anionic, nonionic, amphoteric or ~witterionic detergent active compounds, the . .

. . .

.: .

~0~13 cc . 7~1a amounts and types of which are the same as in -the specification of our ~irst afore-mentioned patent application. It i9 preferred to use from about 5~0 to about ~0% of a detergent active compound which does not during use form an insoluble calcium salt, as the use of anionic compounds such as soaps which do form such iDsoluble salts results in substantially decreased detergent properties. Many suitable detergent compounds are commercially available and are fully descxibed in the literature, for example in "Surface Active Agen-ts and Detergents", Volumes 1 and 2 by Schwartz, Perry and Berch However, as mentioned above, at least part of the binding agent used in the calcium carbonate granules may be a detergent active compound, or a mixture thereof, in which case the total amount of detergent active compounds present in the compositions should be within the range mentioned.
In this event the amount of the detergent active compound is preferably from about 0. 5/0 to about 25~ by weight of the calcium carbonate granules. ~he preferred detergent active compounds used in the granules are anionic detergent active compounds, especially alkali metal alkyl sulphates, which also ac-t as dispersing aids.
~ Having regard to the publication of our first afore- ;
; mentioned patent application, the novel granules which contain up to 60% by weight of calcium carbonate should contain either not more than S% by weight of detergent active compound or not more than 10% by weight of alkali metal carbonate.
In addition to the essential ingredients mentioned above, it is permissible to include in the detergent compositions any of the optional detergent ingredients which are conventionally added to detergent compositions~ Such optional ingredients are generally the same as those set out in the specifications of our afore-mentioned patent applications. Principal amongst such additives are sodium silicates which improve the physical properties of the detergen~ compositions, and also have a bene-ficial effect on detergency due to the pH buffer e~fect, usually cC.761a I.~ 9~3 in the rang~ pll 9 to li :f~r i`al)ric washing purposes. Some sodium silicates, (eg Na20:S-iO2, 1:1-1:3.4), preferably alkaline or neutral silicate, are beneficially included in the detergent base powders so as to give an amount of silicate of 5 from about 5% to about 15% by weight in the final compositions.
Sodium silicates may also act, either alone or with other materials, as binding agents for the calcium carbonate granules. The resultant granules are strong and resistant to mechanical damage, but they also tend -to have decreased dispersing properties in water. When sodium silicates are used as binding agents, it is desirable therefore to use them at low levels, eg from about 0. 5% to about 10% by weight of the granules, in admixture with other binding agents.
The detergent base powder may be made using conventional slurry making and spray drying processes or in other known ways. Normally, it should have approximately the same bulk density as the calcium carbonate granules with which it is admixed in order to minimise segrega'vion, ie from about 0.16 to about 0.96 gm/cc, and a similar particle si~e range, ie - 20 about 0.1 to about 2.5 mm.
The only essential ingredient in tbe detergent base powder is a detergent active compound or mixture thereof, as all the alkali metal carbonate may be contained in the calcium carbonate granule. However, in practice some or all of the alkali metal carbonate i3 normally included in the de-tergent base powder, along with other optional detergent ingredients such as sodium silicate as mentioned above.
It should a~so be noted that the presence of condensed phosphates has a deleterious effect on the properties of the detergent compositions as they interfere with the c~.761a precipitation of calcium carbonate; it is therefore preferred to have no more than abou-t 0.05% P, which is equivalent to about 0.2% sodium tripolyphosphate~ in the detergent compositions.
The invention is illustrated in more detail by the following Examples in which parts and percentages are by weight, except where otherwise indicated.
Example 1 An aqueous slurry of ~inely divided calcite had some anionic detergent active compound thoroughly mi~ed with it and was then spray dried to give fine granules o~ the following ~ormulation;
Ingredient Calcite 73 Alkyl sulphate2 13 Water to 100 B 1 Calofort U50 supplied by J.E. Sturge Limited of Birmingham, England, having an average primary crystal size of ab~ut 260 ~ an~ a nominal surface area of about 50 m /g (35-45 m /g as determined by the BET method as described above on different batches).

2 Dobanol~ 5 sulphate (sodium salt), obtained by sulphation and neutralisation of Dobanol ~5, synthetic secondary linear predominantly C1~-C15 alcohols ex Shell Chemicals Company.
The granules had a bulk density of 27 lbs/cu ~t (ie about 0.44 gm/cc) and were ~ound to disperse very rapidly and completely on addition to water, even without stirring.
When calcite granules were prepared similarly but without the anionic detergent compound as a binding aid, the granules were less friable but did not disperse when added to water and they merely sank to the bottom in the absence of agitation.

.
Gl~ e r~ ote~s t r~e ~ rk~

~9~13 cc . 7fiia .~ ~

Examples 2-6 Five samples of calcite granules were made in a 2 metre inclined (~irich) pan using calcite powder and with various additives. The calcite was in all cases the same as in Example 1. The granules had the following formulations:

/0 in Examples In~redient 2 3 4 5 6 Calcite 86.0 80.~ 75.3 65.6 64.3 Sodium tolue~e6.0 14.
sulphonate Sodium carbonate - - 20.1 17.7 10.9 Water 8.0 5.2 4.6 16.7 24.8 i Bulk density (gm/cc) - 0.37 0.37 0.44 0.46 ~he dispersibilities of the granules were determined by sprinkling them onto cold water and then aftcr a short time agitating the water. Granules which dispersed immediately were rated "very good", whilst granules which sank without disintegrating were rated "poor~.
Dispersibility ; Without With Example Agitation Agitation 2 very good very good

3 very good very good

4 fair fair ; 25 5 fair good 6 poor poor ; -- 19 -- /-;' ' . :-... . .

cC.76la 90~L3 In all cases the granules had better physical properties than calcite granules without any binding agent. The granules of Examples 2-5 had acceptable ~ispersing characteristics, but Example 6 had rela~ively poor properties in this respect which could be allevia-ted by the use of higher levels of sodium carbonate, as in Example 5.
The calcite granules of Examples 1-6 were all suitable for admixing with detergent base powders to make detergent compositions with good detergent properties.
Exam~les 7-16 A series of calclte granules were prepared by spray drying aqueous calcite slurries to which different binding agents were added. In all except Exa~ple 13 the binding agent was incorporated into the slurry before the calcite, i5 which was ad~ed in powder form for Example 9 and otherwise added as a settled aqueous paste containing aboùt 30% solids.
Tbe slurry temperatures were about 80C. ~he spray dried granules had the following formulations and properties:

- 2~ _ /

, :, ': ' -' L3 cc.76l~l 'P
~D . I
., o o . , , , , I . . . .
~, ., . , . ~ ~ o o GO ~
U~ o .1 ~ o C" C~
., ~ U~ ., o o C5) o o o C`~l . . . . . . . . . .
~1 ~ .1 ~ o o 0 ~
U~ ., O ~D ~ ~ C~
~3 ~1 U~) ~rl ~ O Q
~1 0 .1 .
~rl t~ OD ' .1 . I
'æ.~ .~ ) o Q
CS~
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. 0~ I I . I I I I . .
~1 ~ ~D ~ O O
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ODI I I II I I
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. ~ CD a~ ~ ~ ' : ~ ~1 E-~ O ~ ~I Q O
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Q~ C4 ' ' - a ~ ~ O ~D
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t~ ~Q 61 f~ O
d ~1 ~ rQ ~ ~ t-a~rl , ~ E3 ~ ~I t;3a) ~1 o ~ ~1 ~
.. ~rl ~ ~ ~rl ~~1 ~ ~ 3 ~ ~O
b r-l C~ ~ ~ ~~ ~ ~~ ~1 3t~

:
''' ,, -: - : - ' ~ ~9~3 cc . 761a As used in Example i.
Pr~epared from Dobanol ~G, as in Example 1.

Natural montmorillonite clay, from ~ritish l)rug Houses, ~redispersed in water before slurry making.

4 Prepared from Dob~ 55, linear secondary alkyl (C -C 5) ben~ene obtained from Shell Chemicals Co~an~ .
Determined by sieve analysis using a standard procedure with a stack of sieves, followed by calculation to give the average size according to the relative amounts retained in the sieves.
The spray dried granules were assessed for dispersibility and iO found to be better than all-calcite granules, the spray dried granules of Example 13 being particularly good in this respect, with the granules of Example 11 being less sati.s-f'actory. ~he granules were also assessed for friability and dustiness, and found to be generally acceptable provided they were not handled exceptionally roughly during subsequent transporting, mixing and packaging. The granules made with ; the sodium carbonate and bentonite as binding agents were noticeably bet-ter in this respect compared with the granules in which detergent active compounds were used as binding agents.
The spray dried-granules of Examples 7-9 were added to base detergent powders of` the following formulations:
Parts In~redient Base powder A Base powder B

Sodium alkylibenzene 16 sulphonate Nonionic detergent compound2 - 12 Soap ~ 4 Sodium metasilicate 5 5 Sodium carbonate 30 30 ~ denote~ cle h~

., cC.7~1a As u~ed in Example 19.
Tergitol~ ~_S-99 a condensation product of linear secondary alcohol (C -C ) with nine moles of ethylene oxide, froml~nion Carbide Corporation.
Sodium soap prepared from an 80:20 mixture of tallow and coconut ~atty acids.
The granules and the ba~e powder~ were mi~ed ~o as to give about 30% of sodium carbonate and about 35% of calcite in the final compositions~ which were found to have satisfactory detergent properties, with the anionic compositions made with Base Powder A being particularly good in this respect as well as having good dispersing properties.
Although the granules and the ba~e powder were separately prepared by ~pray drying and then admixed in this Example, similar results can be achieved by simultaneously spray drying two separate ~lurrie~ in a single drying tower, to ~orm both the granule~ and the base powder which are mixed as they leave the tower.
Examples l? and 18 ; Granules were made in a pan granulator to the ~ollowing formulations:
~ ;
Ingredient Example 17 E~ample 18 ' Calcite1 25,0 33.3 Sodium carbonate (anhydrous) 27.3 25.5 Sodium toluene sulphonate 2.7 Sodium alkyl sulphate1 - 0.6 Water 45.0 40.5 Bulk density (gm/cc) 0.43 0.90 1 A9 u~ed in Example~ 9 and 10.

~denotes t~ ~r~ :
- 23 ~

, .
' ~9~i3 cc . 761a The granules were then mixed with a base powder containing further sodium alkyl sulphate, sodium alk~line silicate and sodium carbonate to give products having the nominal formulation:
Ingredient ~
Sodium alkyl sulphate 16 Sodium carbonate 40 Sodium alkaline silicate 15 Calcite ~
Water (and minor additive) to 100 These compositions had good detergencies particularly at higher temperatures, with the product containing the ; granules of Example 18~having better dispersion properties and improved detergency building as assessed by the free calcium ion concentrations in the wash solution.
Similar results were obtained when the sodium alkyl sulphate in the granules of Example 18 was repLaced by sodium (C12-~15) alkyl - 3E0 sulphate.
Examples 19-23 Calcite granules were prepared by spray drying calcite slurry containing binding agents to give granules of the following formulations:
. .
In~redient 19 20 21 22 23 Calcitel 52 60 42 52 62 Sodium alkyl sulphate 21 24 18 21 -Sodium alkaline silicate 2~ 12 35 2~ 9 Sodium toluene sulphonate - - - - 10 Water ~ to 100 ~
1 Calcite at surface area of about 40 m2/g determined by the BE~ method as described above, and was supplied by J.E. Sturge Limited as an aqueous slurry containing 20% solid.
- 2~ - /

~9~3 cc . 761a ~he granules had bulk densities of between 20 and 24 lbs/cu ft ~ie 0.32 to 0.38 gm/cc) and average particle sizes between 0.35 and O.SS mm. ~he granules were all suitable for inclusion in detergent compo~itiong, with the granule~ o~ higher alkyl sulphate content having better dispersing properties and those o~ higher silicate content having better physical properties.
xamples 24 and 25 Calcite slurry was granulated with anhydrous sodium carbonate in a granulator to give granules o~ the following formulations:

In~redient 25 25 Calcite 51.2 36.1 Sodium carbonate 18.0 34,6 Water ` 30.8 29.3 These granules had acceptable bulk densities and friabilitie~ and adequate di~persibility in water, and were ~uitable for admixlng with detergent base powders to form detergent compositions.
, ~
; Calcite granules were made to the ~ollowing formulation:
In~redient Sodium linear secondary alkyl 2.9 (C~ 5) sulphate : 25 Calcite1 29.2 - Sodium carbonate58.2 Water 9~7 1 The calcite had a sur~ace area of about 80 m2/g determined by the BET method as described above, and ~a~ supplied in the form o~ a 30% solids ~ilter cake by Solvay et Cie.
- 30 The granules were made by normal slurry making and spray drying techniques, the order o~ addition of the ingredients to the ~lurry being as shown above except that the water was added first. The slurry moisture content was about 45%, - 25 ~

~Q69~13 cc . 761a : with a slurry temperature of about 90C. The slurry was spray dried in a counter-current spray drying tower with an air inlet temperature of about 315C and an outlet temperature of about 100C. The resultant granules had an average particle size of about 0.5 to 0.6 mm and a bulk density of 18 lb/cu ft (ie 0.29 gm/cc), and were free flowing and had satisfactory water dispersibility properties (the latter were improved in particular by the addition o~ the sodium alkyl sulphate).
- 1051.5 parts of the calcite granules were admixed with 48.5 parts of a similarly spray dried detergent base powder having the following formulation and properties:
In~redient . Sodium linear secondary alkyl 31.0 (C11-C15) benzen0 sulphonate Sodium alkaline silicate 20.6 Sodium toluene sulphonate 3.1 Sodium carbonate 31.0 Minor ingredients ~ol Water 10.2 Bulk density 0.26 gm/cc Particle size range0.6-0.95 mm The resultant detergent composition then had the followlng formulation':

.
: ;:

~ - 26 - /

.: .. - : .

9~ cC.761a Ingredient ~ :
Sodium linear secondary alkyl 1500 ~ C15) benzene sulpbonate Sodium linear secondary alkyl 1.5 (C1~-C15) sulphate Sodium alkaline silicate 10.0 Sodium carbonate ~5.0 Calcite 15.0 Sodium toluene sulphonate 1.5 Minor ingredients ~preservatives, 2.0 fluorescent agents, etc) Water 10.0 The resultant mixed detergent compositions were evaluated for detergency and inorgani¢ deposition and found ' to he satis~actory in both these respects. In particular the composition was found to be comparable in detergency properties with a commercially available product containing 33~ sodiu~ tripolyphosphate.

, . . .
'':

- 27 - ***

.

Claims

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

1. A process for making a detergent composition compris-ing from about 5% to about 40% by weight of a detergent active compound, from about 10% to about 75% by weight of an alkali metal carbonate detergency builder and from about 5% to about 60% by weight of finely divided calcium carbonate having a surface area of from about 5 m2/g to about 150 m2/g, by admixing a detergent base powder comprising the detergent active compound and from 0% to about 75% of the alkali metal carbonate with granules formed of from about 25% to about 99.5% by weight of the finely divided calcium carbonate and a binding agent which may comprise from 0% to about 75% of the alkali metal carbonate.

2. A process according to claim 1, wherein the alkali metal carbonate is sodium carbonate.

3. A process according to claim 1 wherein the calcium carbonate is calcite.

4. A process according to claim 1, wherein the calcium carbonate has a surface area of at least about 20 m2/g.

5. A process according to claim 4, wherein the calcium carbonate has a surface area of from about 30 to about 100 m2/g.

6. A process according to claim 1, wherein the calcium carbonate granules contain at least 60% by weight of calcium carbonate.

7. A process according to claim 1, wherein the calcium carbonate granules contain from about 2% to about 40% by weight of binding agent.

8. A process according to claim 1, wherein at least part of the binding agent in the calcium carbonate granules is alkali metal carbonate.

9. A process according to claim 1, wherein at least part of the binding agent is an anionic detergent active compound.

10. A process according to claim 9, wherein the amount of the anionic detergent active compound is from about 0.5% to about 25% by weight of the calcium carbonate granules.

11. A process according to claim 9, wherein the anionic detergent active compound is an alkali metal alkyl sulphate.

12. A process according to claim 1, wherein at least part of the binding agent in the calcium carbonate granules is sodium silicate.

13. A process according to claim 12, wherein the amount of the sodium silicate is from about 0.5% to about 10% by weight of the calcium carbonate granules.

14. A process according to claim 1, wherein the calcium carbonate granules are spray dried.

15. A process according to claim 1, wherein the calcium carbonate granules have a bulk density of from about 0.16 to about 0.96gm/cc.

16. A process according to claim 15, wherein the bulk density of the calcium carbonate granules is from about 0.24 to about 0.48gm/cc.

17. A process according to claim 1, wherein the calcium carbonate granules have an average particle size of from about 0.1 mm to about 2.5mm.

18. Granules of finely divided calcium carbonate having a surface area of from about 5 m2/g to about 150 m2/g, compris-ing from about 25% to about 99. 5% by weight of the calcium carbonate and from about 0. 5% to about 75% by weight of a bind-ing agent, provided that if the granules contain up to 60% by weight of calcium carbonate they should contain either not more than 5% by weight of a detergent active compound or not more than 10% by weight of alkali metal carbonate, said granules having a bulk density of from about 0.16 to about 0.96gm/cc.

19. Granules according to claim 18, wherein the calcium carbonate is calcite.

20. Granules according to claim 18, wherein the calcium carbonate has a surface area of at least about 20 m2/g.

21. Granules according to claim 20, wherein the calcium carbonate has a surface area of from about 30 to about 100 m2/g.

22. Granules according to claim 18, wherein at least part of the binding agent is an alkali metal carbonate.

23. Granules according to claim 22, wherein the alkali metal carbonate is sodium carbonate.

24. Granules according to claim 18, comprising from about 2g to about 40% by weight of binding agent.

25. Granules according to claim 18, wherein at least part of the binding agent is an anionic detergent active compound.

26. Granules according to claim 25, wherein the amount of the anionic detergent active compound is from about 0.5% to about 25% by weight of the calcium carbonate granules.

27. Granules according to claim 25, wherein the anionic detergent active compound is an alkali metal alkyl sulphate.

28. Granules according to claim 18, wherein at least part of the binding agent is sodium silicate.

29. Granules according to claim 28, wherein the amount of the sodium silicate is from about 0.5% to about 10% by weight of the calcium carbonate granules.

30. Granules according to claim 18, produced by a spray-drying process.

31. Granules according to claim 18, having a bulk density of from about 0.24 to about 0.48gm/cc.

32. Granules according to claim 18, having an average particle size of from about 0.1mm to about 2.5mm.

33. Granules according to claim 18, prepared from never-dried calcium carbonate.

34. A detergent composition comprising a detergent base powder which contains from about 5% to about 4% of a detergent active compound (based on the composition) and granules of calcium carbonate having a surface area of from about 5 m2/g to about 150 m2/g, comprising from about 25% to about 99.5%
by weight of the calcium carbonate and from about 0.5% to about 75% by weight of a binding agent, provided that if the granules contain up to 60% by weight of calcium carbonate they should contain either not more than 5% by weight of a detergent active compound or not more than 10% by weight of alkali metal carbonate, said granules having a bulk density of from about 0.16 to about 0.96gm/cc, the percentages being based on the weight of the granules except where otherwise indicated.