CA2169770A1 - Process for making detergent compositions - Google Patents

Abstract

A process for making a high active granular detergent component or composition having a bulk density of at least 650 g/l which comprises the steps of: i) making a paste or liquid which comprises at least 40 % by weight of a surfactant selected from anionic and nonionic surfactants, ii) mixing said surfactant paste or liquid with a powder to form a mixture which may be in the form of either a paste of a cohesive powder; iii) forming granules by fine dispersion mixing or granulation of said mixture, optionally in the presence of an effective amount of one or more additional powders; wherein the powder used in step ii) comprises a free-flowing, premixed powder comprising from 0.5 % to 10 % by weight of a hydrophobic silica and from 75 % to 99.5 % by weight of a hygroscopic powder comprising a polymer.

Description

2 1 6 ~ 7 7 0 PCT~S94/09325 Process for Making Detergent Compositions The ~sent invention relates to a ~ocess for making granular detergent which have a high surfactant activity and which are free-flowing and rapidly dissolving. In ~nother aspect the invention relates to a premixed free-flowing powder which comprises hyd~o~hobic silica and a hy~LGscopic powder which comprises a polymer. In a third aspect the invention relates to high active, high bulk density granular detergent compositions.

Granular detergent granules comprising low levels of certain polymers which provide structure or strength to the granule are known and have been made by spray dv~ing aqueous solutions or slurries comprising the polymer.
However, spray dried granules have low bulk densities (for example 350-550 g/l). Further treatment is necessary in order to increase the bulk density and various methods have been proposed to do this. One approach is to apply -chAnical work to the spray dried powder in order to reduce its porosity and increase its bulk density. Another approach is to granulate a liquid or paste, typically in D the presence of a powder. Polymers may be added to such a SUB~TITUTE SHEET (~JLE 26) WO9~/05449 PCT~US94/09325 ~ 6977~

process either as a component of the liquid/paste, or as a component of the powder. Examples in the prior art of the such processes include:

EPA 421 664, published on 10th April, 1992, describes high bulk density c _~itions comprising polymer and water soluble inorganic component. Compositions comprising surfactants and hydrophobic silica are not foreseen.

EPA 510 746, published on 28th October, 1992, describes a process of fine dispersion mixing of a viscous surfactant paste with detergent powders to form a granular detergent.
Polymers and silica are mentioned as useful ingredients in such a detergent _- ~sition. However there is no suggestion of how they may be most usefully combined.

EPA 513 824, published on l9th t~ov. her, 1992 describes a oce~s for -~ing gr~n~ r detergents which compris- up to 60% by weight of nonionic surfactant. It suggests that various powder c_ _nents may be premixed in order to improve physical properties, but it does not indicate which powders may be advantageously premixed.

When it is required to use higher levels of poly~ers in high bulk density granular detergent components, the hygroscopic nature of many polymers presents a problem. In particular this is the case when the component also comprises a high level of surfactant. Hygroscopic powders which are bound into the surface of the detergent - _"ent cause the component to readily absorb water which encourages gel formation, caking of the detergent powder and poor dispensing and dissolution properties.

The present invention aims to solve this problem by providing a process in which the surface of hygroscopic powders which comprise polymers is modified before the high bulk density detergent granules are formed. This surface SU~STITUTE SHE~ ULE 26) W095/~5419 2 1 6 9 7 7 0 PCT~S94/09325 modification effect is provided by premixing the hyqroæcopic powder with hydrophobic silica.
t The present invention further aims to provide a high bulk density detergent _- sition which comprises high levels of detergent surfactant and polymers.

Summary of the Invention A ~,ocess for making a high active granular detergent component or composition having a bulk density of at least 650 g/l which comprises the steps of:
i) ~kjng a paste or liquid which comprises at least 40% by weight of a surfactant selected from anionic and nonionic surfactants, ii) mixing said surfactant paste or liquid with a powder to form a mixture which may be in the form of either a paste or a cohesive powder;
iii) forming granules by fine Aisp~rsion mixing or granulation of said mixture, optionally in the presence of an effective amount of one or more additional powders;
wherein the powder used in step ii) comprises a free-flowing, premixed powder comprising from 0.5% to 10% by weight of a hydrophobic silica and from 75% to 99.5~ by weight of a hygroscopic powder comprising a polymer.

Detailed Description of the Invention The first aspect of the present invention relates to a process for making a high active granular detergent StJBSTlTUTE SHEFr (I~ULE 26) WO95/05449 PCTrUS94/09325 1 7 ~

component or composition having a bulk density of at least 650 g/l. The process comprises the steps of: , i) making a paste or liquid which comprises at least 40% by weight of a surfactant selected from anionic and nonionic surfactants, ii) mixing said surfactant paste or liguid with a powder wherein the powder is a free-flowing, p,~- iY~ ~o~ r comprising from 0.5% to 10% by weight of a hydrophobic silica and from 7S% to 99.5% by weight of a hygroscopic powder comprising a polymer. The resulting mixture m~y be in the form of either a paste or a cohesive powder; and iii) forming granules by fine dispersion mixing or granulation of said mixture, optionally in the presence of an effective amount of one or more additional powder~.

Preferably the polymer c_ Dn~nt of the h~Lo~cspic powder is chosen from the group consisting of polymers or co-polymers of acrylic and maleic acid, polyvinyl pyrrolidone, polyvinyl pyrridine N oxide, carboxymethyl cellulose, poly~spartate, and starch. Preferably the hydrophobic silica is used as a coating agent to coat, or partially coat the outer surfaces of the hy~ copic powder.

one method of preparing the hygroscopic powder which is useful in the present invention is to use a spray drying technique, wherein a two fluid nozzle is used in the spray drying step. Most preferably c~ ~essed air is used as one of the fluids in the two fluid nozzle.

In a preferred embodiment of the process the p,.- ixed hydrophobic silica and hygroscopic polymer is mixed with the surfactant paste prior to the fine dispersion mixing of step iii). One way of doing this is to use an extruder, for example a twin screw extruder.

An example of a range of typical compositions of the premixed hydrophobic silica and hygroscopic polymer is:

SUBSTITUTE SHEET l~lJLE 26) W095/05449 ~ I ~ 9 7 7 0 PCT~S94/09325 a) from 80% to 95~ by weight of a polymer;
b) from 1% to 5~ by weight of hydrophobic silica;
?~ C) Up to 20% by weight of zeolite In a further aspect the present invention relates to a granular detergent component having a bulk density of at least 650 g/l and comprising:
a) at least 35% (preferably at least 45%, more preferably at least 55%) by weight of surfactant;
b) from 5% to 25% (preferably from 8% to 15%) by weight polymer;
c) fram 0.05% to 2.5% (preferably from 0.5% to 1%) by weight of hydrophobic silica;

The details of the process will now be described in more detail.

Firstly a high active surfactant paste is prepared. One or various aqueous pastes of the salts of anionic surfactants is preferred for use in the pl~ent invention, preferably the sodium salt of the anionic surfactant. In a preferred : ho~i ent, the anionic surfactant is preferably as concentrated as possible, (that is, with the lowest possible moisture content possible that allows it to flow in the manner of a liquid) so that it can be pumped at t~ -ratures at which it remains stable. While granulation using various pure or mixed surfactants is known, for the present invention to be of practical use in industry and to result in particles of adequate physical properties to be incorporated into granular detergents, an anionic surfactant should preferably be a part of the paste in a concentration of above 10% by weight, preferably from 10-95%, more preferably from 20-95%, and most preferably from 40%-95~ by weight.

SUBSTITUTE SHE~ WLE 26) W095/05449 7 7 o PCT~S94/09325 It is preferred that the moisture in the surfactant aqueous paste is as low as possible, while maintaining paste fluidity, since low moisture leads to a higher concentration of the surfactant in the finishe~ particle.
Preferably the paste contains between 5 and 40% water, more preferably between 5 and 30S water and most preferably between 5 and 20~ water. A highly attractive mode of operation for lowering the moisture of the paste prior to entering the agglomerator without problems with very high viscosities is the installation, in line, of an at - ~eric or a vacuum flash drier whose outlet is connected to the agglomerator.

It is preferable to use high active surfactant pastes to minimize the total water level in the system during iYing~ granulating and drying. Lower water levels allow for: (1) a higher active surfactant to builder ratio, e.g., 1:1; (2) higher levels of other liquids in the formula without causing dough or gr~n~ stic~ir~Y~; (3) lcs5 cooling, due to higher allowable granulation t: _- ~tures;
and (4) less granular drying to meet final moisture limits.

Two important parameters of the surfactant pastes which can affect the mixing and granulation step are the paste temperature and viscosity. Viscosity is a function, among others, of concentration and t~ -rature, with a range in this application from about 5,000 cps to 10,000,000 cps. Preferably, the viscosity of the paste entering the system is from about 20,000 to about 100,000 cps. and more preferably from about 30,000 to about 70,000 cps. The viscosity of the paste of this invention is measured at a temperature of 70C and at a shear rate of from 10 to 50 sec~l, in particular, about 25 sec~1.
The paste can be introduced into the mixer at an initial temperature between its softening point (generally in the range of 40-60C) and its degradation point (depending on the chemical nature of the paste, e.g. alkyl SUBSTITUTE SHEET t~ULE 2~J

W095/05449 PCT~S94/09325 ~ 2169770 sulphate pastes tend to degrade above 75-85C). High tf ~ratures reduce viscosity simplifying the pumping of the paste but result in lower active agglomerates. The use of in-line moisture reduction steps (e.g. flash drying), however, require the use of higher temperatures (above 100C). In the present invention, the activity of the agglomerates is maintained high due to the elimination of moisture.

The introduction of the paste into the mixer can be done in many ways, from simply pouring to high pressure pumping through small holes at the end of the pipe, before the entrance to the mixer. While all these ways are viable to manufacture agglomerates w$th good physical properties, it has been found that in a pre~erred embodiment of the present invention the extrusion of the paste re~ults in a better distribution in the mixer which improves the yield of particles with the desired size. Most preferably a twin screw extruder is used. The use of high pumping ~ res prior to the entrance in the mix-r results in an i,.
activity in the final agglomerates. By combining both effects, and introducing the paste through holes (extrusion) small ~nol~qh to allow the desired flow rate but that k~ep the pumping ~re~s~re to a maximum feasible in the system, highly advantageous results are achieved.

High Active Surfactant Paste The activity of the aqueous surfactant paste is at least 30% and can go up to about 95~; preferred activities are : 60-90% and 70-80%. The balance of the paste is primarily water. At the higher active concentrations, little or no builder is required for cold granulation of J the paste. The resultant concentrated surfactant granules can be added to dry builders or powders or used in conventional agglomeration operations. The aqueous surfactant paste contains an organic surfactant selected SUBSTITUTE SHE~T (~LE 26~

WO95/OS449 PCT~US94/09325 - ~ 6977~ ~

from the group consisting of anionic, nonionic, zwitterionic, ampholytic and cationic surfactants, and mixtures thereof. Anionic surfactants are preferred. r Surfactants useful herein are listed in U.S. Pat. No.

3,664,961, Norris, issued May 23, 1972, and in U.S. Pat.
No. 3,919,678, Laughlin et al., issued Dec. 30, 1975.
Useful cationic surfactants al80 include those described in U.S. Pat. No. 4,222,905, Cockrell, issued Sept. 16, 1980, and in U.S. Pat. 4,239,659, Murphy, i~sued Dec. 16, 1980.
However, cationic surfactants are generally less compatible with the aluminosilicate materials herein, and thus are preferably used at low levels, if at all, in the present c_ -~itions. The following are representative examples of surfactants useful in the present - _sitions.

Water-soluble salts of the higher fatty acids, i.e., "soaps", are useful anionic surfactants in the c -~itions herein. This includes alkali metal soaps such as the sodium, potassium, ammonium, and alkylammonium salts of higher fatty acids containing from about 8 to about 24 carbon atoms, and preferably from about 12 to about 18 carbon atoms. Soaps can be made by direct saponification of fats and oils or by the neutralization of free fatty acids. Particularly useful are the sodium and potassium salts of the mixtures of fatty acids derived from coconut oil and tallow, i.e., sodium or potassium tallow and coconut soap.

Useful anionic surfactants also include the water-soluble salts, preferably the alkali metal, ammonium and alkylolammonium salts, of organic sulfuric reaction products having in their molecular structure an alkyl group containing from about 10 to about 20 carbon atoms in a linear or branched chain and a sulfonic acid or sulfuric acid ester group. (Included in the term "alkyl" is the alkyl portion of acyl groups.) Examples of this group of synthetic or natural surfactants are the sodium and SUBSTITUTE SHEET (~ULE 26j Wo 95/05449 '~I
L 1 6 9 7 7 0 PCT~94/093~5 potassium alkyl sulfates, especially those obtained by sulfating the higher alcohols (C8-C18 carbon atoms) such as those produced by reducing the glycerides of tallow or coconut oil; and the sodium and potassium alkyl benzene sulfonates in which the alkyl group contains from about 9 to about 15 carbon atoms, in straight or branched chain configuration, e.g., those of the type described in U.S.
Pat. Nos. 2,220,099 and 2,4~7,383. Especially valuable are linear straight chain alkyl benzene sulfonates in which the average number of carbon atoms in the alkyl group is from about 11 to 13, abbreviated as Cll-C13 LAS.

Other anionic surfactants herein are the sodium alkyl glyceryl ether sulfonates, especially those ethers of higher alcohols derived from tallow and CGCOnU- oil; sodium coconut oil fatty acid monoglyceride sulfonates and sulfates; sodium or potassium salts of alkyl phenol ethylene oxide ether sulfates containing from about 1 to about 10 units of ethylene oxide per molecule and wherein the alkyl ~ ou~s contain from about 8 to about 12 carbon atoms; and sodium or potassium salts of alkyl ethylene oxide ether sulfates containing from about 1 to about 10 units of ethylene oxide per molecule and wherein the alkyl group contains from about 10 to about 20 carbon atoms.

Other useful anionic surfactants herein include the water-soluble salts of esters of alpha-sulfonated fatty acids containing from about 6 to 20 carbon atoms in the fatty acid group and from about 1 to 10 carbon atoms in the ester group; water-soluble salts of 2-acyloxy-alkane-1-sulfonic acids containing from about 2 to 9 carbon atoms in the acyl group and from about 9 to about 23 carbon atoms in the alkane moiety; alkyl ether sulfates containing from about 10 to 20 carbon atoms in the alkyl group and from about 1 to 30 moles of ethylene oxide; watersoluble salts of olefin sulfonates containing from about 12 to 24 carbon atoms; and beta-alkyloxy alkane sulfonates containing from SUBSTITUTE SHEET (I~ULE ~6) W095/0S449 PCT~S94/09325 ~ ~q~ 10 about 1 to 3 carbon atoms in the alkyl group and from about 8 to about 20 carbon atoms in the alkane moiety. Although the acid salts are typically ~i~c~c~e~ and used, the acid neutralization cam be performed as part of the fine dispersion mixing step.

- The preferred anionic ~urfactant pastes are mixtures of linear or branched alkylbenzene sulfonates having an alkyl of 10-16 carbon atoms and alkyl sulfates having an alkyl of 10-18 carbon atoms. These pastes are usually pro~uce~ by reacting a liquid organic ~aterial with sulfur trioxide to produce a sulfonic or sulfuric acid ~nd then neutralizing the acid to produce a salt of that acid. The salt is the surfactant paste ~isc~F~ throughout this ~ocl -nt. The sodium salt is preferred due to end performance benefits and cost of NaOH vs. other neutralizing agents, but iæ not required as other agents such as KOH may be used.

Water-soluble nonionic surfactants are also us~ful as surfactants in the compositions of the invention. TnA~e~, preferred ~oc~sr~s use anionic/nonionic blends. A
particularly preferred paste comprises a blend of nonionic and anionic surfactants havinq a ratio of from about 0.01:1 to about 1:1, more preferably about 0.05:1. Nonionics can be used up to an equal amount of the primary organic surfactant. Such nonionic materials include compounds pro~uce~ by the condensation of alkylene oxide groups (hydrophilic in nature) with an organic hydrophobic compound, which may be aliphatic or alkyl aromatic in nature. The length of the polyoxyalkylene group which is condensed with any particular hydrophobic group can be readily adjusted to yield a water-soluble compound having the desired degree of balance between hydrophilic and hydrophobic elements.

SUBSTITUTE SH~ET (I~ULE 26~

4~ PCT~S94/09325 2~6q77~

Suitable nonionic surfactants include the polyethylene oxide condensates of alkyl phenols, e.g., the condensation products of alkyl phenols having an alkyl group containing from about 6 to 16 carbon atoms, in either a straight chain or branched chain configuration, with from about 4 to 25 moles of ethylene oxide per mole of alkyl phenol.

Preferred nonionics are the water-soluble condensation products of aliphatic alcohols cont~ining from 8 to 22 carbon atoms, in either straight chain or brA~ch~A
configuration, with from 4 to 25 moles of ethylene oxide per more of alcohol. Particularly preferred are the cQn~ncation products of alcohols having an alkyl group containing from about 9 to 15 carbon atoms with from about 4 to 25 moles of ethylene oxide per mole of alcohol; and con~nC~tion products of propylene glycol with ethylene oxide.

Other preferred nonionics are polyhydroxy fatty acid amides which may be pro~ e~ by reacting ~ fatty acid ester and an N-alkyl polyhydroxy amine. The preferred amine for use in the present invention is N-(Rl)-CH2(CH20H)4-CH2-OH and the preferred ester is a C12-C20 fatty acid methyl ester. Most preferred is the reaction product of N-methyl glucamine with C12-C20 fatty acid methyl ester.

Methods of manufacturing polyhydroxy fatty acid amides have been described in WO 92 6073, published on 16th April, 1992. This application describes the preparation of polyhydroxy fatty acid amides in the presence of solvents.
In a highly preferred embodiment of the invention N-methyl glucamine is reacted with a C12-C20 methyl ester. It also says that the formulator of granular detergent compositions may find it convenient to run the amidation reaction in the presence of solvents which comprise alkoxylated, especially ethoxylated (EO 3-8) C12-C14 alcohols (page 15, lines 22-27).

- S~STITUTE SltEEl ~ULE 26~

W095/05449 PCT~S94/09325 ., ~ .

~ ~ 6q 7 7 ~ 12 Another class of nonionic surfactants comprises alkyl polyglucoside compounds of general formula R0 (CnH2nO)tzx wherein Z is a moiety derived from glucose; R is a saturated hydrophobic alkyl group that contains from 12 to 18 carbon atoms; t is from 0 to 10 and n is 2 or 3; x is from 1.3 to 4, the compounds including less than 10%
unreacted fatty alcohol and less than 50% short chain alkyl polyglucosides. Compounds of this type and their use in detergent _ ,ositions are disclosed in EP-B 0070074, 0070077, 0075996 and 0094118.

Semi-polar nonionic surfactants include water-soluble amine oxides containing one alkyl moiety of from about 10 to 18 carbon atoms and 2 moieties selected from the group consisting of alkyl groups and hydroxyalkyl ~o~
containing from l to about 3 carbon ato~s; water-soluble pholphin~ oxides containing one alkyl moiety of about lO to 18 carbon atoms and 2 moieties selected from the group consisting of alkyl groups and hydroxyalkyl groups containing from about 1 to 3 carbon atoms; and water-soluble sulfoxides containing one alkyl moiety of from about 10 to 18 carbon atoms and a moiety selected from the group consisting of alkyl and hydroxyalkyl moieties of from about 1 to 3 carbon atoms.

Ampholytic surfactants include derivatives of aliphatic or aliphatic derivatives of heterocyclic secondary and tertiary amines in which the aliphatic moiety can be either straight or branched chain and wherein one of the aliphatic substituents contains from about 8 to 18 carbon atoms and at least one aliphatic substituent contains an anionic water-solubilizing group.

SUBSTITUTE S~IEET (I~ULE 26~

WO95/05449 2 1 6 9 7 7 0 PCT~S94/09325 zwitterionic surfactants include derivatives of aliphatic quaternary ammonium phosphonium, and sulfonium compounds in which one of the aliphatic substituents contains from about 8 to 18 carbon atoms.

Particularly preferred surfactants herein include linear alkylbenzene sulfonates containing from about 11 to 14 carbon atoms in the alkyl group; alkyl sulfates cont~i n i ~g from about 12 to 18 carbon atoms in the alkyl group; coconutalkyl glyceryl ether sulfonates; alkyl ether sulfates wherein the alkyl moiety contains from about 14 to 18 carbon atoms and wherein the average degree of ethoxylation is from about 1 to 4; olefin or paraffin sulfonates containing from about 14 to 16 carbon atoms;
alkyldimethylamine oxides wherein the alkyl group contains from about 11 to 16 carbon atoms; alkyldimethylammonio propane sulfonates and alkyldimethylammonio hydroxy propane sulfonates wherein the alkyl group contains from about 14 to 18 carbon atoms; soaps of higher fatty acids containing from about 12 to 18 carbon atoms; con~ tion products of C9-C15 alcohols with from about 3 to 8 moles of ethylene oxide, and mixtures thereof.

Useful cationic surfactants include water-soluble quaternary ammonium compounds of the form R4R5R6R7N+X-, wherein R4 is alkyl having from 10 to 20, preferably from 12-18 carbon atoms, and R5, R6 and R7 are each C1 to C7 alkyl preferably methyl; X~ is an anion, e.g. chloride.
Examples of such trimethyl ammonium compounds include C12_ 14 alkyl trimethyl ammonium chloride and cocalkyl trimethyl ammonium methosulfate.

Specific preferred surfactants for use herein include:
sodium linear c11-c13 alkylbenzene sulfonate; alpha-olefin sulphonates; triethanolammonium Cll-C13 alkylbenzene sulfonate; alkyl sulfates, (tallow, coconut, palm, synthetic origins, e.g. C45, etc.); sodium alkyl sulfates;

SUBSrl ~UTE SHEE'r ~RULE 26) W095/05449 PCTrUS94tO9325 ~ ~ ~q ~ 4 methyl ester sulphonate; sodium coconut alkyl glyceryl ether sulfonate; the sodium salt of a sulfated condensation product of a tallow alcohol with about 4 moles of ethylene oxide; the condensation product of a coconut fatty alcohol with about 6 moles of ethylene oxide; the condensation product of tallow fatty alcohol with about ll moles of ethylene oxide; the condensation of a fatty alcohol containing from about 14 to about 15 carbon atoms with about 7 moles of ethylene oxide; the condensation product of a Cl2-Cl3 fatty alcohol with about 3 ~ole~ of ethylene oxide; 3-(N,N-dimethyl-N-coconutalkylammonio)-2-hydroxypropane-l-sulfonate; 3-(N,N-dimethyl-N-coconutalkylammonio)-propane-l-sulfonate; 6- (N-dodecylbenzyl-N,N-dimethylammonio) hexanoate;
dodecyldimethylamine oxide; coco..u~alkyldimethylamine ox$de; and the water-soluble sodium and potassium salts of coconut and tallow fatty acids.

The surfactant paste described above is formed into granules by fine dispersion mixing in the ~.~sQnce of a powder. In the present invention, the surfactant paste is either intimately mixed with a component which is a free-flowing mixture of a hydrophobic silica and a hy~Loscopic powder comprising a polymer prior to granulation, or said free-flowing mixture is added directly to the mixer/granulator as one of the powder components of the granulation step.

The hydrophobic silica which is present at a level of from 0.5% to 10% of the component is a highly dispersed amorphous silicon dioxide. It is c_ -rcially available in many forms. Most commonly silica has a tapped density of from 50 g/l to 120 gtl. The specific surface area of the particles ranges from 25 square metres per gram to 800 square metres per gram.

SUBSTITUTE SH~ET (RULE ~6) W095/~5449 2 1 6 9 7 70 PCT~594/~9325 The surface of silica particles can be chemically modified to change their behaviour with respect to water. For example,silica particles may be treated with organosilanes to make the particles predominantly hydrophobic. It has been found that silicas must be hydrophobised to be useful in the present invention.

In =~ -rcial practice, silica i8 usually prepared by one of two techniques; either by precipitation or by high temperature flame hydrolysis. Precipitated silicas generally have an agglomerate size of from 3 mi~ ers to 100 micrometers, whereas fumed silicas (made by flame hydrolysis) usually have primary particles which are generally spherical and have an average diameter of from 7nm to 40nm. Fumed silicas having an average primary particle size of from 7 to 25 nanometers are preferred in the present invention.

Examples of silicas which are particularly useful in the nt invention include those supplied by Degussa AG, Frankfurt, Germany under the Trade Name "Aerosil". Aerosil R972 has been found to be particularly useful. This silica is a hydrophobic, fumed silica which has a specific surface area of about 110 square metres per gram and an average primary particle size of 16 nanometers.

The other essential feature of the powder is a hygroscopic powder which comprises a polymer. By hygroscopic it is meant that the powder shows more than 50% moisture uptake at 80% relative humidity at 25C. To measure this a 3 gram sample of the powder, having an average particle size of 250 micrometers, is placed on an 80mm diameter petri dish.
The sample is dried in a vacuum oven at 40C for 48 hours, and the dry weight recorded. The sample is then placed in a relative humidity and temperature control unit. (That is, any sample ch~ h~r which has controllable % relative humidity (80+/-2%) and temperature (25+/-1C) ) . The unit is SUBSTITUTE SHEET (RULE 26) -W095/05449 PCT~S94/0932S

~ ~911 16 set at 80% relative humidity and 25C for at least 8 hours.
The sample weight is then recorded again.

For the purposes of the present invention a powder which absorbs more than 50% of its dry weight at 80% relative humidity and 25C is considered to be hyqroscopic.

The powder may consist exclusively of a polymer, or, alternatively, the powder may further comprise other detergent ingredients such as surfactants, builders (especially zeolites) etc. The powder may be prepared by any suitable means including spray drying of an aqu~ous solution or slurry of the powder components. one p~rticularly preferred method is spray drying using a two-fluid nozzle, the process of which is de~cribed in ~ore detail below.

Polymers which are particularly useful as components of the hygroscopic powder of the ~L ~ ~ L invention include sodium carboxy-lower alkyl celluloses, sodium lower alkyl celluloses and sodium hydroxy-lower alkyl ce~ o~ such as sodium carboxymethyl cellulose, sodium methyl cellulose and ~odium hydroxypropyl cellulo~e, polyvinyl alcohols (which often also include some polyvinyl acetate), polyvinyl pyrrolidone, polyethylene glycol, polyaspartate, polyacrylamides, polyacrylates and various copolymers, such as those of maleic and acrylic acids. Molecular weights for such polymers vary widely but most are within the range of 2,000 to 100,000.

Most preferred are polymeric polycarboxyate builders are set forth in U.S. Patent 3,308,067, Diehl, issued March 7, 1967. Such materials include the water-soluble salts of homo-and copolymers of aliphatic carboxylic acids such as maleic acid, itaconic acid, mesaconic acid, fumaric acid, aconitic acid, citraconic acid and methylenemalonic acid.

SUBSrlML SHEET (WLE 26) -WO95/~544s ~ 1 6 9 7 7 0 PCT~S94/~93~5 It is a further feature of the present invention that the hygroæcopic powder and the hydrophobic silica are thoroughly premixed before the granulation step with the surfactant paste. A process for this is described in more detail below.

Optionally other powders may be used in the process of granulating the surfactant pagte. Examples of suitable powders will be described below in more detail.

The detergent compositions herein can contain crystalline aluminosilicate ion exchange material of the formula Nazt(AlO2)z (SiO2)y] xH2o wherein z and y are at least about 6, the molar ratio of z to y is from about 1.0 to about 0.4 and z is from about 10 to abo~t 264. ~ ~L~hous hydrated aluminosilicate materials useful herein have the empirical formula MZ(zAlo2-ysio2) wherein M is sodium, potassium, ammonium or substituted ammonium, z is from about 0.5 to about 2 and y i5 1, said material having a magnesium ion exchange capacity of at least about 50 milligram equivalents of CaCO3 hardness per gram of anhydrous aluminosilicate. Hydrated sodium Zeolite A with a particle size of from about 1 to 10 microns is preferred.

The aluminosilicate ion exchange builder materials herein are in hydrated form and contain from about 10% to about 28% of water by weight if crystalline, and potentially even higher amounts of water if amorphous.
Highly preferred crystalline aluminosilicate ion exchange materials contain from about 18~ to about 22% water in their crystal matrix. The crystalline aluminosilicate ion exchange materials are further characterized by a particle size diameter of from about 0.1 micron to about 10 microns.

SUBSTITUTE SH~T ~ULE 26) W095/05449 PCTrUS94/09325 ~6911~

Amorphous materials are often smaller, e.g., down to less than about 0.01 micron. Preferred ion exchange materials have a particle size diameter of from about 0.2 micron to ~bout 4 microns. The term "particle size diameter" herein represents the average particle size diameter by weight of a given ion exchange material as determined by conv~l.tional analytical techniques such as, for example, microscopic determination utilizing a scanning ele_~LG.. microscope.
The crystalline aluminosilicate ion exchange materials herein are usually further characterized by their calcium ion exchange capacity, which is at least about 200 mg equivalent of CaCO3 water hardness/g of aluminosilicate, calculated on an anhydrous basis, and which generally i5 in the range of from about 300 mg eg./g to about 352 mg eq./g.
The aluminosilicate ion ~YrhAnge materials herein are still further characterized by their calcium ion exchange rate which is at least about 2 grains Ca++/gallon/minute/gram/gallon of aluminosilicate (anhydrous basis), and generally lies within the range of from about 2 grains/gallon/minute/gram/gallon to about 6 grains/gallon/minute/gram/gallon, based on calcium ion hardness. Optimum aluminosilicate for builder ~UL~
exhibit a calcium ion exchange rate of at least about 4 grains/gallon/minute/gram/gallon.

The amorphous aluminosilicate ion exchange materials usually have a Mg++ exchange of at least about 50 mg eq.
CaCO3/g (12 mg Mg++/g) and a Mg++ exchange rate of at least about 1 grain/gallon/minute/gram/gallon. Amorphous materials do not exhibit an observable diffraction pattern when examined by Cu radiation (1.54 Angstrom Units).

Aluminosilicate ion exchange materials useful in the practice of this invention are ~o ~rcially available. ~he aluminosilicates useful in this invention can be crystalline or amorphous in structure and can be naturally occurring aluminosilicates or synthetically derived. A

SllBSrITUTE SHEEl (RULE 26) W09S/0544~ PCTrUS94109325 .9 method for producing aluminosilicate ion exchange materials is discussed in U.S. Pat. No. 3,985,669, Krummel et al., issued Oct. 12, 1976, incorporated herein by reference.
Preferred synthetic crystalline aluminosilicate ion ~Y~h~nge materials useful herein are available under the designations Zeolite A, Zeolite B, and Zeolite X. In an especially preferred ~ ho~i -nt, the crystalline aluminosilicate ion PY~h~ge material has the formula Nal2[(A12)12(SiO2)12] xH20 wherein x is from about 20 to about 30, especially about 27 and has a particle size generally less than about 5 microns.

The granular detergents of the present invention can contain neutral or alkaline salts which have a pH in solution of seven or greater, and can be either organic or inorganic in nature. The builder salt assists in providing the desired density and bulk to the detergent granules herein. While some of the salts are inert, many of them also function as detergency builder materials in the laundering solution.

Examples of neutral water-soluble salts include the alkali metal, ammonium or substituted ammonium chlorides, fluorides and sulfates. The alkali metal, and especially sodium, salts of the above are preferred. Sodium sulfate is typically used in detergent granules and is a particularly preferred salt. Citric acid and, in general, any other organic or inorganic acid may be incorporated into the granular detergents of the present invention as long as it is chemically compatible with the rest of the agglomerate composition.

Other useful water-soluble salts include the compounds commonly known as detergent builder materials. Builders are generally selected from the various water-soluble, alkali metal, ammonium or substituted ammonium phosphates, SUB~mrrE SHEET (FlIJLE ~6) W095/05449 PCT~S94/09325 ~ 6977 polyphosphates, phosphonates, polyphosphonates, carbonates, silicates, borates, and polyhydroxysulfonates. Preferred are the alkali metal, especially sodium, salts of the above.

Specific examples of inorganic rhosph~te builders are sodium and potassium tripolyphos~hAte, pyrophosph~te, polymeric metaphosphate having a degree of polymerization of from about 6 to 21, and orthorhosrh~te. Examples of polyphosphonate builders are the sodium and potasgium salts of ethylene diphosphonic acid, the sodium and potassium salts of ethane l-hydroxy-1,1-dirhssrhonic acid and the sodium and potassium salts of ethane, l,l,2-triphosrhQnic acid. Other phosphorus builder compounds are disclosed in U.S. Pat. Nos. 3,159,581; 3,213,030; 3,422,021; 3,422,137;
3,400,176 and 3,400,148, incorporated herein by reference.

Examples of nonEhosphorus, inorganic builders are sodium and potassium carbonate, bicarbonate, sesquicarbonate, tetraborate decahydrate, and silicate having a molar ratio of SiO2 to alkali metal oxide of from about 0.5 to about 4.0, preferably fro~ about 1.0 to about 2.4.

As mentioned above powders normally used in detergents such as zeolite, carbonate, silica, silicate, citrate, phosphate, perborate, etc. and process acids such as starch and sugars, can be used in preferred embodiments of the present invention. Optionally, other components may be added at any one of the stages of the process of the present invention, or they may be mixed with or sprayed on to the granular detergents of the present invention.

Another optional detergent composition ingredient is a suds suppressor, exemplified by silicones, and silica-silicone mixtures. Silicones can be generally represented by alkylated polysiloxane materials while silica is SUB~ITtJT~ SHEET (~ULE 26) W095/05449 2 1 6 9 7 7 0 PCT~S94/09325 normally used in finely divided forms, exemplified by silica aerogels and xerogels and hydrophobic silicas of various types. These materials can be incorporated ~s particulates in which the suds suppres~or is advantageously releasably incorporated in a water-soluble or water-dispersible, substantially non-surface-active detergent-impermeable carrier. Alternatively the suds suppressor can be dissolved or dispersed in a liquid carrier and applied by spraying on to one or more of the other components.

As mentioned above, useful silicone suds controlling agents can comprise a mixture of an alkylated siloxane, of the type referred to hereinbefore, and solid silica. Such mixtures are prepared by affixing the silicone to the surface of the solid silica. A preforred silicone suds controlling agent is ~Lesented by a hydLophobic silanated (most preferably trimethyl-silanated) silica having a particle size in the range from 10 n~n~ -~ers to 20 nanometers and a specific surface area above 50 m2/g, intimately admixed with dimethyl silicone fluid having a molecular weight in the range from about 500 to about 200,000 at a weight ratio of silicone to silanated silica of from about 1:1 to about 1:2.

A preferred silicone suds controlling agent is disclosed in Bartollota et al. US Patent 3,933,672. Other particularly useful suds suppressors are the self-emulsifying silicone suds ~uppressors, described in German Patent Application DTOS 2,646,126 published April 28, 1977. An example of such a compound is DC0544, commercially available from Dow Corning, which is a siloxane/glycol copolymer.

The suds suppressors described above are normally employed at levels of from 0.001% to 0.5% by weight of the composition, preferably from 0.01% to 0.1% by weight.

SUBSTITUTE StlEE~ ULE 26) W095/05449 PCT~US94/~9325 ~ 6~77~ 22 The preferred methods of incorporation comprise either application of the suds suppressors in liquid form by spray-on to one or more of the major components of the c ,-sition or alternatively the formation of the suds suppressors into separate particulates that can then be mixed with the other solid components of the composition.
The incorporation of the suds modifiers as separate particulates also permits the inclusion therein of other suds controlling materials such as C20-C24 fatty acids, microcrystalline waxes and high MWt copolymers of ethylene oxide and propylene oxide which would otherwise adversely affect the ~ispersibility of the matrix. Techni~ues for forming such suds modifying particulates are disclosed in the previously mentioned Bartolotta et al US Patent No.
3,933,672.

Another optional ingredient useful in the present invention i5 one or more enzymes.

Preferred enzymatic materials include the commercially available amylases, neutral and alkaline proteA~
lipAq~s, esterases and cell~ e-- conventionally incorporated into detergent compositions. Suitable enzymes are discussed in US Patents 3,519,570 and 3,533,139.

The process of fine dispersion iying or granulation will typically be carried out in a high speed mixer. The term "fine dispersion mixing and/or granulation", as used herein, means mixing and/or granulation of the mixture in a fine dispersion mixer at a blade tip speed of from about 5m/sec. to about 50 m/sec., unless otherwise specified.
The total residence time of the mixing and granulation process is preferably in the order of from 0.1 to 10 minutes, more preferably 0.1-5 and most preferably 0.2-4 SUB~TITUTE SHEET (~ULE 26) W09S/05449 2 1 6 9 7 7 0 PCT~S94/09325 minutes. The more preferred mixing and granulation tip speeds are about 10-45 m/sec. and about 15-40 m/sec.
J

Any apparatus, plants or units suitable for the processing of surfactants can be used for carrying out the process according to the invention. Suitable apparatus includes, for example, falling film rulrhonating reactors, digestion tanks, esterification reactors, etc. For mixing/
agglomeration any of a number of mixers/agglo~erators can be u#ed. In one preferred embodiment, the ~L~C--~ of the inve~tion is continuously carried out. Especially preferred are mixers of the FukaeR FS-G series manufactured by Fukae Powtech Kogyo Co., Japan; this apparatus is essentially in the form of a bowl-~Ape~ vessel accessible via ~ top port, provided near its base with a stirrer having a substantially vertical axis, and a cutter positioned on a side wall. The stirrer and cutter may be operated in~p~nd~ntly of one another and at separately variable ~pee~c. The vessel can be fitted with a cooling jacket or, if necessAry, a ~.yuy_..ic unit.

Other similar mixers found to be suitable for use in the ~r oCe35 of the invention include DiosnaR V series ex Dierks & Sohne, Germany; and the Pharma MatrixR ex T K
Fielder Ltd., England. Other mixers believed to be suitable for use in the process of the invention are the FujiR VG-C series ex Fuji Sangyo Co., Japan; and the RotoR
ex Zanchetta & Co srl, Italy.

Other preferred suitable equipment can include EirichR, series RV, manufactured by Gustau Eirich Hardheim, Germany; LodigeR, series FM for batch mixing, series Baud KM for continuous mixing/agglomeration, manufactured by Lodige Machinenbau GmbH, Paderborn Germany; DraisR T160 series, manufactured by Drais Werke GmbH, Mannheim Germany;
and WinkworthR RT 25 series, manufactured by Winkworth Machinery Ltd., Berkshire, England.

S~JB~l~E SHEE~ t~LE 26) W095/05449 PCT~S94/09325 ~,~ 6q_17~ ~

The Littleford Mixer, Model ~FM-130-D-12, with internal chopping blades and the cuisinart Food P-oc~s~or, Model #DCX-Plus, with 7.75 inch (19.7 cm) blades are two examples of suitable mixers. Any other mixer with fine dispersion mixing and granulation capability and having a residence time in the order of 0.1 to 10 minutes can be used. The "turbine-type" impeller mixer, having several blades on an axis of rotation, is preferred. The invention can be practiced as a batch or a continuous ~LOCe~8.

The preferred operating temperatures for the agglomeration step should also be as low as pos~ible since this leads to a higher surfactant concentration in the finisheA particle.
Preferably the t~ -rature during the agglomeration i~ less than 100C, more preferably between 10 and 90C, and most preferably between 20 and 80C. Lower operating t~ -ratures useful in the ~LOC~SS of the ~sent invention ~ay be achieved by a variety of ~ethods known in the art such as nitrogen cooling, cool water jacketing of the eguipment, addition of solid cO2, ~nd the like; with a preferred method being solid C02, and the most preferred method being nitrogen cooling.

The granules formed in the high speed mixer may still have a higher moisture content than desired. In this case the desired moisture content of the free flowing granules of this invention can be adjusted to levels adequate for the int~n~e~ application by drying in conventional powder drying equipment such as fluid bed dryers. If a hot air fluid bed dryer is used, care must be exercised to avoid degradation of heat sensitive components of the granules.
It is also advantageous to have a cooling step prior to large scale storage. This step can also be done in a conventional fluid bed operated with cool air. The drying/cooling of the agglomerates can also be done in any SUBSrlTUTE SHEET (~ULE 26) W09~/05449 PCT~S94/09325 ~ 21 6~770 other equipment suitable for powder drying such as rotary dryers, etc.

For detergent applications, the final moisture of the agglomerates needs to be maintained below levels at which the agglomerates can be stored and transported in bulk.
The exact moisture level ~p~n~s on the composition of the agglomerate but is typically achieved at levels of 1-8%
free water (i.e. water not associated to any crystalline species in the agglomerate) and most typically at 2-4%.

Further details of the preferred process of the present invention are given below.

A preferred ~occ~s for the preparation of the hy~c-coric powder ifi by spray drying. A mo5t pref~rred ~ uses a two fluid nozzle or spinning d~gk. Th~se nozzles are particularly use~ul to make polymer containing qranules for use in the ~c~Be-~ invention, wherein the con~ntrated polymer-containing slurry or solution has a high viscosity and/or a non-Newtonian rheology. Such a slurry is diffiCUlt to spray dry through a conventional pressure nozzle.

Suitable two fluid nozzles and disks are supplied by Delavan, and described in their "Spray Drying Manual" and by Spraying systems co., and described in their Tec~niCal Manual No. 402.

The atomisation in two-fluid nozzles is derived from energy in compressed air, gas or pressurised steam. Preferably air-atomising nozzles are used. ~he atomisation in spinning disks is derived from the kinetic energy of the disk on to which the slurry or solution is sprayed.
.

SU~STIT1JTE SHEEr ~LE 2~

wo95/0544s PCTrUS94/09325 ~ ~q17~ ~

The slurry or solution may comprise other detergent ingredients, such as those described herein, as well as polymer. One preferred composition is polymer and aluminosilicate, especially zeolite A. C -~itions of this type, as well as proc~ss~s for making them have been described in DE 33 16 513, published on 8th November, 1984.

When the hygroscopic powder has been prepared, it i8 the nec~ss~ry to coat the surface with hydrophobic silica.
Suitable hydrophobic silicas have been described above.

The hygroscopic powders can be added placed in a low shear mixer or rotating drum. The hydrophobic silica can then be added to the drum or mixer while it is in motion. The hydrophobic silica coats the h~.&_csric ~ r ~nd makes the particles free flowing. The flow aid creates a hyd~ophobic layer which protect~ against moisture. The invention can be practised aa a batch or a continuous process. Alternatively, another ~L GCe85 which i8 suited to the present invention is that of fluidi~ed bed coating. In a fl~ bed process the solid particles ~re largely separate from one another, i.e. in a fluidi~ed state, and can therefore be effectively coated by the hydrophobic silica.

The extruder fulfils the functions of pumping and mixing the vificol~C surfactant paste on a continuous basis. A basic extruder consists of a barrel with a smooth inner cylindrical surface. Mounted within this barrel is the extruder screw. There is an inlet port for the high active paste which, when the screw is rotated, causes the paste to be moved along the length of the barrel.
The detailed design of the extruder allows various functions to be carried out. Firstly additional ports in the barrel may allow other ingredients, including the chemical structuring agents to be added directly into the barrel. Secondly a vacuum pump and a seal around the shaft SUBSTITUTE SHE~T (~ULE 26) WO9S/054~19 2 1 6 9 7 7 0 PCT~S94/U932S

of the screw allows a vacuum to be drawn which enables the moisture level to be reduced. Thirdly means for heating or cooling may be installed in the wall of the barrel for temperature control. Fourthly, careful design of the extruder screw promotes i Ying of the paste both with itself and with other additives.
A preferred extruder is the twin screw extruder. This type of e~truder has two screws mounted in parallel within the same barrel, which are made to x~tate either in the same direction (co-rotation) or in opposite directions (counter-rotation). The co-rotating twin screw extruder i3 the most preferred piece of eguipment for ufie in this invention.
An extruder is particularly useful in a preferred . ho~i ~nt of the present invention because the hygroscopic powder/hydrophobic silica can be added to the surfactant paste via an inlet port in the extruder and can be considered as chemical structuring agents. The extruder helps to ensure thorough and intimate mixing of the paste and the powder. In this embodiment of the invention the extruder conveys the conditioned paste which now comprises poly~er and hydrophobic silica into the mixer where fine ~sporsion and granulation takes place. Suitable mixers have been defined above.

Suitable twin screw extruders for use in the p~ vnt invention include those supplied by : APV Baker, (CP
series); Werner and Pfleiderer, (Continua Series); Wenger, (TF Series); Leistritz, (ZSE Series); and Buss, (LR
Series).

The extruder a' ~ws the paste to be conditioned by moisture and tempe~ ~re reduction. Moisture may be removed under vacuum, preferably between O mmHg (gauge) and -55 mmHg (ga~ge), (O - 7.3 kPa below atmospheric pressure).

Temperature may be reduced by the addition of solid carbon dioxide or liquid nitrogen directly into the SUB~TITUTE SHEET (~ULE 26~

W O 9S/05449 PCTrUS94/09325 ~ ~ 6 q 7 1 ~ 28 extruder barrel. Preferably liquid nitrogen i8 used at up to 30% by weight of the paste.

EXAMPLES

In these examples the following abL,eviations have been used:

C25E3 C12-15 alkyl ethoxylate, with an average of 3 ethoxy yL GU~S per molecule GA N-methyl glucamide PVP Polyvinyl pyrrolidone Example 1 An aqueous surfactant paste was prepared comprising:
62.5~ by weight sodium alkyl sulphate having substantially C14 and C15 alkyl ~h~ in~;
15.5% by weight sodium alkyl ester sulphate having substantially C13 to C15 alkyl chains and sn average of 3 ethoxy ~oups per molecule;
17% by weight of water and the balance being mainly comprised of unreacted alcohol and s~lphAtes.
A ~_~'er premix was prepared by mixing the sodium salt of a co-polymer of maleic and acrylic acid with 2% by weight of hydrophobic silica (Aerosil R972, trade name, supplied by Degussa) in a Loedige FM130D (trade name) mixer for 3Q
seconds.
The aqueous surfactant paste and the premixed co-polymer /
hydrophobic silica were then intimately mixed in a twin screw extruder with a barrel in 6 sections (manufactured by werner & Pfleiderer, C58).The resulting viscous paste was SlJBSTlTUTE SHEE~`t~uLE 26) W095/05449 2 ~ 6 9 7 7 0 PCT~S94109325 then placed in a Loedige FM130D (trade name) batch ploughshAre mixer containing a mixture of 2 parts zeolite A
to 1 part finely divided light carbonate. The mixer is operated until granulation takes place.
The resulting agglomerates were transferred to a fluid bed drier and then classified through mesh sieves to ~. v~
oversize and fine particles.
~he aqglomerates formed had a ~urfactant content of 40% by weight, a polymer level of 12% by weight, a ~ilica level of 0.24% by weight and an equilibrium relative humidity level of 10% at room temperature.
The granules formed have excellent flow and handling properties.

C~. -rative Example 2 The process of example 1 was repeated, except that the co-polymer of maleic and acrylic acid was not mixed wit~ 2% of hydrophobic silica. The silica level in the f~ni ~^~
agglonerates was o%~ and the agglomerates after granulation, drying and classification F~l:wed poor handling and flow properties.

Example 3 An aqueous surfactant paste was prepared comprising:
62.5% by weight sodium alkyl sulphate having substantially C14 and C15 alkyl chains;
15.5% by weight sodium alkyl ester sulphate having substantially C13 to C15 alkyl chains and an average of 3 ethoxy groups per molecule;
17% by weight of water and the balance being mainly comprised of unreacted alcohol and sulphates.
A powder premix was prepared by mixing the sodium salt of a co-polymer of maleic and acrylic acid with 2% by weight of hydrophobic silica (Aerosil R972, trade name, supplied by Degussa) batchwise in a ribbon blender.

SUB~T~TUTE SHEET ~ULE 2~

W095/OS449 PCT~US94/09325 q 11 ~ ~ .

The aqueous surfactant paste and the premixed co-polymer /
hydrophobic silica were then intimately mixed in a twin screw extruder (manufactured by Werner & Pfleiderer, C170).The resulting viscous paste was extruded directly into a Loedige CB30 (trade name) high speed mixer containing a mixture of 1 part zeolite A to 1 part finely divided light carbonate. The mixer operates on a continuous basis and dis~hArges directly into a Loedige KM (trade name) continuous plolyhF~Are mixer.
The resulting agglomerates were transferred to a fluid bed drier, cooled in a fluid bed cooler and then classiSied through mesh sieves to L~ ~Ve oversize and fine particles-The agglomerates formed had a surfactant content of 40% by weight, a polymer level of 11.2% by weight, a ~ilica level of 0.22% by weight and an equilibrium relative humidity level of 10% at room t~ -rature.
The granules formed have excellent flow and handling properties.

Example 4 An Eirich RV02 high shear mixer was charged with a mixture of 32 parts Zeolite A to 32 parts finely divided carbonate.
A mixture of 10 parts PVP and 1 part hydrophobic silica (Aerosil R972, trade name, supplied by Degussa) was premixed and added to the mixer. 25 parts of a nonionic surfactant paste of containing GA and C25E3 in a 25/75 ratio were also added to the mixer.
The mixer is operated at a speed of 2500 rpm until granulation takes place. The mixer is then stopped and the agglomerates are cooled in a fluid bed and classified through mesh sieves. The resulting agglomerates have excellent physical properties including flowability Hnd r have a bulk density of 750 g/l.

SUBSrlTUTE SHEET ~I~VLE 26) W095/05449 2 1 6 9 7 7 0 PCT~S94/09325 ' Example 5 The process of example 4 was repeated replacing the 32 parts of carbonate by 32 parts of finely divided citrate~

- Example 6 This example describes the p~C~F~ in batch mode in a lab scale high shear mixer lfood ~locc~sor).The sodium ~alt of the copolymer of maleic and acrylic acid is premix~d with the hydrophobic silica. The mixer is first charged with a mixture of powders to be used, in this case:

percent by weight sodium salt of the copolymer of maleic and acrylic acid 10 h~d~v~hobic silica (Aerosil R972) Carbonate 32 Zeolite A
total 75 A nonionic surfactant paste containing a GA/C25E3 mixture at a ratio of 50/50 was added at 25 percent by weight before starting the mixer. The mixer was then operated until granulation took place. The mixer was then stopped and the agglomerates were cooled in a fluid bed and classified through mesh sieves. The resulting agglomerates had excellent physical properties including flowability and had a bulk density of 700 g/l.

SUBSTITUTE ~HEEr (RULE 26)

Claims (16)

WHAT IS CLAIMED IS:

1. A process for making a high active granular detergent component or composition having a bulk density of at least 650 g/l which comprises the steps of:
i) making a pumpable liquid which comprises at least about 40% by weight of a surfactant selected from anionic and nonionic surfactants, ii) mixing said pumpable liquid with a powder to form a mixture which is in the form of a paste;
iii) forming granules by fine dispersion mixing or granulation of said pasty mixture, optionally in the presence of an effective amount of one or more additional powders;
characterised in that the powder used in step ii) is a free-flowing, premixed powder comprising from about 0.5% to about 10% by weight of a hydrophobic silica and from about 75% to about 99.5% by weight of a hygroscopic powder comprising a polymer.

2. A process according to claim 1 wherein said polymer component of said hygroscopic powder is chosen from the group consisting of polymers or co-polymers of acrylic and maleic acid, polyvinyl pyrrolidone, polyvinyl pyrridine N oxide, carboxymethyl cellulose, polyaspartate, starch and mixtures thereof.

3. A process according to claim 1 wherein the hygroscopic powder is prepared by spray drying, wherein a two fluid nozzle is used in the spray drying step.

4. A process according to claim 3 wherein compressed air is used as one of the fluids in the two fluid nozzle.

5. A process according to claim 1 wherein the premixed powder comprising hydrophobic silica and hygroscopic powder is mixed with the surfactant paste prior to the fine dispersion mixing of step iii).

6. A process according to claim 1 wherein the hydrophobic silica is used as a coating agent to coat, or partially coat the outer surfaces of the hygroscopic powder.

7. A process according to claim 1 wherein the hygroscopic powder comprises a) from about 80% to about 95% by weight of a polymer;
b) from about 1% to about 5% by weight of hydrophobic silica;
c) up to about 20% by weight of zeolite

8. A process for making a high active granular detergent component or composition having a bulk density of at least 650 g/l which comprises the steps of:
i) making a pumpable liquid which comprises at least about 40% by weight of a surfactant selected from anionic and nonionic surfactants, ii) mixing said pumpable liquid with a powder to form a mixture which is in the form of a cohesive powder;
iii) forming granules by fine dispersion mixing or granulation of said cohesive powder mixture, optionally in the presence of an effective amount of one or more additional powders;
characterised in that the powder used in step ii) is a free-flowing, premixed powder comprising from about 0.5% to about 10% by weight of a hydrophohic silica and from about 75% to about 99.5% by weight of a hygroscopic powder comprising a polymer.

9. A process according to claim 8 wherein said polymer component of said hygroscopic powder is chosen from the group consisting of polymers or co-polymers of acrylic and maleic acid, polyvinyl pyrrolidone, polyvinyl pyrridine N oxide, carboxymethyl cellulose, polyaspartate, starch and mixtures thereof.

10. A process according to claim 8 wherein the hygroscopic powder is prepared byspray drying, wherein a two fluid nozzle is used in the spray drying step.

11. A process according to claim 10 wherein compressed air is used as one of thefluids in the two fluid nozzle.

12. A process according to claim 8 wherein the premixed powder comprising hydrophobic silica and hygroscopic powder is mixed with the surfactant paste at the same time as the fine dispersion mixing of step iii).

13. A process according to claim 8 wherein the hydrophobic silica is used as a coating agent to coat, or partially coat the outer surfaces of the hygroscopic powder.

14. A process according to claim 8 wherein the hygroscopic powder comprises:
a) from about 80% to about 95% by weight of a polymer;
b) from about 1% to about 5% by weight of hydrophobic silica;
c) up to about 20% by weight of zeolite

15. A granular detergent component having a bulk density of at least 650 g/l, comprising:
a) at least about 35% by weight of surfactant;
b) from about 5% to about 25% by weight polymer;
c) from about 0.05% to about 2.5% by weight of hydrophobic silica;

16. A granular detergent component according to claim 15 comprising:
a) at least about 45% by weight of surfactant;
b) from about 8% to about 15% by weight polymer;
c) from about 0.5% to about 1% by weight of hydrophobic silica;