CA2175335A1

CA2175335A1 - Spray drying process for making a low or nil phosphate automatic dishwashing detergent composition

Info

Publication number: CA2175335A1
Application number: CA 2175335
Authority: CA
Inventors: John Michael Jolicoeur; Edward Joseph Wandstrat
Original assignee: Individual
Current assignee: Procter and Gamble Co
Priority date: 1993-11-01
Filing date: 1994-10-11
Publication date: 1995-05-11
Also published as: EP0726932A1; AU8076094A; WO1995012651A1

Abstract

The present invention relates to a process for making a high bulk density granular automatic dishwashing detergent composition comprising spray drying a mixture of alkali metal silicate and water soluble organic polymer. The spray dried granule is combined with conventional nonphosphate automatic dishwashing detergent ingredients to form a final product.

Description

wo 95112651 2 t 7 ~ 3 3 5 PCTIUS9~/1151fi Spray dry~ng process for mak1ng a low or n~l phosphate automat1c d1shwashlng detergent compos1t~on T~('T-T~I('AT.FJFr n The present invention relates to a process for spray drying cu,.,p~ of high bulk density low or nil phosphate granular automatic di~h~aa;lillg detergent C In l,~L~,ul~ly, the invention relates to forming granules by spray 10 drying alkali metal silicate and water-soluble polymer.
BA('KGROUND OF T~ VENTIO~
Granular automatic diallw~lalli~lg detergent '~ " and their CIJ.I.~ , e.g. builders, alkaline salts, sodium silicate, low-foaming sllrf~ f~nfc chlorine bleach, etc, are well known in the art. A number of processes have been15 described for the production of such diallw~a;lillg detergent .
Generally, ~.~cl;-~ and/or admixing techniques are used in ~. .r.. 1...;..~ a granular automatic diall~ g detergent c~ For example, U.S. Patent 4,379,069, Rapisarda et al., issued April 5, 1983, U.S.
Patents 4,427,417, Porasik, issued January 24, 1984, and 3,888,781, Kingry et al., issued June 10, 1975. However, because of the demand for compact detergent ~, . alternate mcans must be found for il~u.l!ulaL~ high levels of liquid (i.e. nonionic surfactant, pul~ laL~:, and the like) as the amount of solid . decreases.
Spray drying techniques have been employed in producing laundry detergents; however, spray drying processes have not been ~At~ applied to automati6 dia;~ detergents because the process often results in low bulk density products. In addition, because of phosphate reversion during spray drying (resulting in insoluble residue) this process had been avoidcd for traditional phosphate containing automatic diallw~all;llg detergent formulas.
It has now been found that a nil or low-phosphate, high bullc density granular automatic d;all ' detergent ~ l can be achieved by spray drying an aqueous mixture of alkali metal silicate and water-soluble organic polymer (i.e.~ul~ ' ) and combining the resulting granule with ,' p~ automatic ~' ~l,il~g detergent ingredients. The ingredients may be combined by post admixing dry solids andlor ~plr~mPr~in~ to achieve the desired high bulk density WO gS112651 PCT/US9 1/11516 2t7s33'j ~
product of greater than about 0.7 grams/cc. Surprisingly, the . o ,~ can clean dishware as effectively as phosphate containing .~
.
SUMMARY OF TH~ INVF'`ITION
The present invention . ~ processes for making low or nil 5 phosphate, high bullc density granular automatic di~l~w~ detergent f~f m~ci~ifm c~ 6-(a) spray drying a mixture comprising from about 20% to about 90%, byweight of said mixture, of alkali metal silicate solution and from about 5% to about 30%, by weight of said mixture, of water-soluble organic polymer solution to form free flowing gr,nules; and (b) combining from about 20% to about 80%, by weight of said of said granules of step (a) with from about 1% to about 90% of non-phosphate detergent builder;
wherein said . , has a bulk density of greater than about 0.7 grams/cc and 15 less than about 0.5% phosphate in the form of l , ' ~,u~.
Preferably a ~ ' product is desired wherein the spray dried granules and non-phosphate detergent builder are admixed. The . , also preferably comprises nonionic surfactant, enzymes and oxygen bleach.
DETATT T-T~ ~F~iCl~TT'TION OF I~TF INVFl`lTlON
The granular detergent ~ process of the present invention comprises spray drying a mixture of alkali metal silicate and water-soluble organic polymer to form free flowing granules; and combining said granules with non-phosphate detergent builder. Low foaming nonionic surfactant and bleach are 25 preferable optional ingredients. The component materials are described in detail below.
A~li Mf~
The _ . ~ of the type described herein deliver their bleach and alk,linity tJ the wash water very quickly. ~ " they can be aggressive to 30 metals, dishware, and other materials, which can result in either riicrolf~l~ti-~m by etching, chemical reaction, etc. or weight loss. The alkali metal silicates hereinafter described provide protection against cosion of metals and against attack on dishware, including fine china and glassware.
The SiO level should be from about 4% to about 25%, preferably from 35 about 5% to about 20%, more preferably from about 6% to about 15%, based on the weight of the automatic d;~l" ' Q detergent: , The ratio of SiO
to the alkali metal oxide (M2O, where M=alkali metal) is typically from about I

WO95/12651 21 7~3~S PCT/VS9~/11!i16 to about 3.2, preferably from about 1.6 to about 3, more prefesbly from about 2 to about 2.4. The alkali metal silicate is an aqueous solution, having from about 30% to about 60%, more preferably from about 40% to about 50% water.
The present invention comprises spray drying a mixture containing water-roluble organic polymer discussed herein below and from about 20% to about 90%, preferably from about 40% to about 70æalkali metal silicate solution.
~'' '~' ''~ C& Polymer The water soluble organic polymer, is employed in the present invention at levels from about 0.1% to about 20%, preferably from about 1% to about 10%, most preferably from about 3% to about 8%, by weight of the . . The water-soluble organic polymer is in aqueous solutions and can be alkali metal salts of a ~Iy~bu)~ylic acid.
The aqueous solution of a water-soluble polymer can comprise from about 10% to about 70%, preferably from about 20% to about 60%, more preferably from about 30% to about 50%, most preferably from about 40% to about 50%, by weight of the water-soluble polymer of water. The aqueous rolution of a water-soluble polymer comprises from about 5% to about 30%, by weight of the spray dry mixture.
Solutions of the film-forming polymers described in U.S. Pat. No.
4,379,080 (Murphy), issued Apr. 5, 1983, r ' ~ herein by reference, can be used as the water-soluble organic polymer of the present invention.
Suitable polymers for use in the aqueous solutions are at least partially neutralized or aL~cali metal,: or substituted (e.g., mono-, di-or i ' ) salts of PUIY~bUA.~I~C acids, excluding those with potential '' ' ' ~ or explosive properties. Wherl the sodium silicate and polymer are spray dried together the acid form of the polymer should be avoided ro that interaction with the silicate does not occur. The alkali metal, especially sodium ~;alts are most preferred. While the molecular weight of the polymer can vary over a wide range, it preferably is from about 1,000 to about 500,v00, morepreferably from about 2,000 to about 25û,000, and most preferably is from about 3,000 to about 100,000.
Other suitable pvlymers include those disclosed in U.S. Patent No.
3,3v8,067 issued March 7, 1967, to Diehl, i.,~ull ~ herein by reference.
Unsaturated acids that can be l,ul~ ~i to form suitable polymeric 35 pulJ~buA.y' include acrylic acid, maleic acid (or maleic anhydride), fumaric acid, itaconic acid, aconitic acid, mesaconic acid, citraconic acid and .~tl-J~ ' acid. The presence of . ~ segments containing no lbVA.y' ' radicals such as ~;-.y' ' ~1 ether, styrene, ethylene, etc. is suitable W095112651 ,, PCTIUS9~1/11516

2~533S 4 provided that such segments do not constitute more than about 40% by weight of the polymer.
Other examples of suitable polymers for use herein are ~ u~ol~ of acrylamide and acrylate having a molecular weight of from about 3,000 to about 100,000, preferably from about 4,000 to about 20,000, and an acrylamide content of less than about 50%, preferably less than about 20%, by weight of the polymer.
Most preferably, the polymer has a mole~ular weight of from about 4,000 to about20,000 and an acrylamide content of from about 0% to about 15%, by weight of the polymer.
Particularly preferred are aqueous solutions of poly~ ' with an average molecular weight in acid form of from about 1,000 to about 10,000, and acrylate/maleate or acrylate/fumarate cul,ul,~ with an average molecular weight in acid form of from about 2,000 to about 8û,000 and a ratio of acrylate of maleate or fumarate segments of from about 30:1 to about 2:1. This and other suitable .u~l.~ based on a mixture of . J mono- and d;~buAy-monomers are disclosed in E~uropean Patent Application No. 66,915, published December 15, 1982, . ' herein by reference.
Other polymers useful herein include the pul~. l}.~l...~ glycols and ~IY~UIUIJJI~ glycols having a molecular weight of from about 950 to about 30,000 which carl be obtained from the Dow Chemical Company of Midland, Michigan. Such li ' for example, having a melting point within the range of from about 30O to about 100oC can be obtained at molecular weights of 1450, 3400, 4500, 6000, 7400, 9500, and 2û,000. Such r ~ are formed by the pul~ iu~ of ethylene glycol or propylene glycol with the requisite number of moles of ethylene or propylene oxide to provide the desired molecular weight andmelting point of the respective pul~. II,yl~ glycol and POIY~UIU~UJh~ glycol.
The ~ulJ. IhJI~ , pul~ul~ and mixed glycols are ~UII~I ' 'l~/
referredTo by means of the structural formula CH CH

XO-(CH2-CH20)m-(CH2-CHO)n-(CH-CH20)o-H
wherein m, n, and o are integers satisfying the molecular weight and given above.
Other polymers useful herein include the cellulose sulfate esters such as cellulose acetate sulfate, cellulose sulfate, IIYdIUA.~t;IJI cellulose sulfate~
I-.~,lhJ' " ' sulfate, and l~d~uAy~JIu~u~ llulu~ sulfate. Sodium cellulose sulfate is the most preferred polymer of this group.

~ WO 9S/126S1 21 7~ 3s PCT/US94111516 (-~ 5 ~
C~IIUA~' ' ~I~Y~- ~1....,.1.~ are also suitable polymers, IJ~uLi~.ul~lLly starches, celluloses and alginates, described in U.S. Pat. No. 3,723,322, Diehl,~, issued Mar. 27, 1973; the dextrin esters of polywbu,~ylic acids disclosed in U.S.
Pat. No. 3,929,107, Thompson, issued Nov. 11, 1975; the hydroAyalkyl starch 5 ethers, starch esters, oxidized starches, dextrins and starch l,.~Jlul~ described in U.S. Pat No. 3,803,285, Jensen, issued Apr. 9, 1974; and the ~buA~ Lcd starches described in U.S. Pat. No. 3,629,121, Eldib, issued Dec. 21, 1971; and the dextrin starches described in U.S. Pat. No. 4,141,841, ~ n~lltl, issued Feb.27, 1979; all . ' herein by reference. These polymers are also often 10 referred to as thickeners. Preferred polymers of the above group are the wbuA~ Lllrl celluloses.
Other useful l,uly~ ' are The term modified pUI~ ' ' is defined as a copolymer which contains as monomer units: a) from about 90% to about 10%, prefesbly from about 80% to about 20% by weight acrylic acid or its salts and b)15 from about 10% to about 90%, preferably from about 20% to about 80% by weight of a substituted acrylic monomer or its salts having the general formula:
IR2 Rll - [ C - C ] -2û
C = O
o I

R
wherein at least one of the ' 'l R, R or R, preferably R or R is a 1 to 4 carbon aIkyl or llydluA~all~l group, R or R can be a hydrogen and R can be a hydrogen or all~ali metal salt. Most preferred is a substituted acrylic monomer wherein R is methyl, R is hydrogen and R is sodium.
3û The low molecular weight ~ol~ ' preferably has a molecular weight of less than about 15,000, preferably from about 500 to about 10,000, most preferably from about 1,000 to about 5,000. The most preferred ~ulr~ly' copolymer has a molecular weight of 3500 and is about 70% by weight acrylic acidand about 3û% by weight methyl acrylic acid.
Suitable modified l)UI~ ly' ~o~ include the low molecular weight cu~ul.~ .s of I ' aliphatic carboxylic acids as disclosed in U.S. Patent 4,530,766, and S,084,535, both of which are , ' herein by reference.

WO 95/12651 PCT/US94/11516 ~
2~'1s33~ --In general, the water-soluble organic polymer can comprise any one or a mixture of the polymers described above.
Non- ' ' Detereency ~uilder The detergency builders used can be any of the non-phosphate detergency builders known in the art, which include the various water-soluble, alkali metal, or substituted carbonates, borates, pOl~ uAy r , ~ ~llb~JA,~- ' (e.g. citrates), and ~vly~L~uAJ- Preferred are the alkali metal, especially sodium, salts of the above and mixtures thereof.
The builder is present in the automatic d;ahw~ all;ll~ detergent ~ in 10 an amount from about 1% to about 90%, preferably frûm about, 5% to about 80%, most preferably 15% to about 75%, by weight, of the automatic d;allw lalu detergent .
Examples of non-l' ,' ua, inorganic builders are aodium and potassium carbonate, L,;~uL , , ' and hydroxide.
Water-soluble, non-l- ,' ua organic builders useful herein include the various alkali n al,: and substituted: polyacetates, ~UbVA~ pVI~-~lUbVA~- ' and ~vl.~l-ydluA~aulfonates. Examples of and ~vly~ubvA~- builders are the aOdium, potassium, lithium, and substituted salts ûf ethylene diamine tetraacetic acid, 20 . ~ acid, tartrate l acid, tartrate disuccinic acid, UAyl~ u~;~l;C acid, carboAy ' ~lu~ ~ acid, mellitic acid, benzene pul~l vA~ acids, and citric acid.
Preferred detergency builders have the ability to remove metal ions other than al~ali metal ions from washing solutions by ~ l~ which as defined 25 herein includes chelation, or by IJlC~;~;laL~V~ reactions. Although sodium lI;~1VI~1- ,- has generally been a particularly preferred detergency builder material, sodium citrate is preferred to reduce the total r- .~ ua level of the of the invention.
P~uli~ul~l.~ preferred automatic d;~ , detergent , of the 30 invention contain, by weight of the ~ . from about 5% to about 40%, preferably from about 10% to about 30%, most preferably from about 15% to about 25X, of sodium carbonate. P~ull~.uldlly preferred sodium citrate with levels from about 5% to about 40%, preferably from about 7% to 30%, most preferably from about 8% to about 20%, by weight of the . are also present Low ~ ~ Nonionic Surfactant ~

- W0951126SI ~ .` i PCT/US94111516 The low foaming nonionic surfactants of the present invention are from about 0.1% to about 10%, preferably from about 0.5% to about 5%, by weight of tbe c~ o~
Herein, by "low foaming" is meant that the nonionic surfactant is suitable for use in an automatic dishwasher.
Reduced surfactant mobility is a ~ in stability of the optional bleach , Preferred surfactant ~ s with relatively low solubility can be ~ ' in . . on~ containing alkali metal ~' ' ' u.,~ or other organic chlorine bleaches without an interaction that results in loss of available chlorine. The nature of this problem is disclosed in U.S. Patent 4,309,299 issued January 5, 1982 to Rapisarda et al and in U.S. Patent 3,359,207, issued December 19, 1967, to Kaneko et al, both patents being iII~,UI~ ' ~ herein by reference.
In a preferred ' :' t, the surfactant is ar~ IUA~' ' ' surfactant derived from the reaction of a lllù.~ll.ydluAy alcohol or aLIcylphenol containing from about 8 to about 20 carbon atoms, excluding cyclic carbon atoms, with from about 6 to about 15 moles of ethylene oxide per mole of alcohol or alkyl phenol on an average basis.
A r . '` ~ preferred ctlluAy' ' nonionic surfactant is derived from a straight chairl fatty alcohol containing from about 16 to about 20 carbon atoms (C alcohol), preferably a C alcohol, condensed with an average of from about tPto about 15 moles, prefera~ly from about 7 to about 12 moles, and most preferably from about 7 to about 9 moles of ethylene oxide per mole of alcohol.
Preferably the: ' y' ' nonionic surfactant so derived has a narrow ethoxylate ~ ' relative to the average.
The e~vAy' ' nonionic surfactant can optionally contain propylene oxide in an amount up to about 15 % by weight of the surfactant and retain the advantages hereinafter described. Preferred surfactants of tbe invention can be prepared by tne processes described in U.S. Patent 4,223,163, issued September 16, 1980, Guilloty, I ' herein by reference.
The most preferred ~ . contains the .~LIIOA~
t.1dlUA,~ I ' ' or alkyl phenol and additionally comprises a PVI~VA~ IU~ yUI~UA~.Uy~ block polymeric compound; the Cl1lUA~
' /dIUAY alcohol or alkyl phenol nonionic surfactant . lg from about 20% to aboout 80%, preferably from about 30% to about 70%, of the total surfactant; , by weight.
Suitable block pOlyuAy~ ylullc PUIYUA~ UYYI~ polymeric ~ - l, ' that meet the ~ described ll~.c;l.b~fvlc include those based on ethylene WO 95~12651 PCTNS94/11516 2t~s33~ --glycol, propylene glycol, glycerol, trimethylolpropaDe and ethyl~ ,;". as the initiator reactive hydrogen compound. Polymeric c~ u ,.l. made from a sequential c;LlluA~ldiu~ aDd ~lu~uA~l~diull of initiator .~ . ' with a single reactive hydrogen atom, such as C 2 18 aliphatic alcohols, do not provide 5 i~L;,r~Luly suds control in the detergent , of the invention. Certain of the block polymer surfactant , _ ' designated PLURONIC(!3 aDd TETRONlCæ by the BASF-WyaDdotte Corp., U'~. ' , Michigan, are suitable in the surfactant . , of the invention.
A ,u~uLi~ ul,ul~ preferred ~ ~ " contains from about 40% to about 70%
10 of a ~ulyuA~uluAu.~ , PUI~UA~ IUIIC block polymer blend comprising about 75%, by weight of the blend, of a reverse block co-polymer of ~I~UA~
and ~I~UA~IU~)jlUII~ containing 17 moles of ethylene oxide and 44 moles of propylene oxide; and about 25%, by weight of the blend, of a block co-polymer of~UIyUA~ and ~UI~VAy~lU~ iDitiated with tri-methylol propane, 15 containing 99 moles of propylene oxi~e and 24 moles of ethylene oxide per mole of trimethylol propane.
Because of the relatively high POI~UA~IU~IU~IC content, e.g, up to about 90% of the bloclc ~I~UA~ ~IYUA~JIU~ - polymeric ~ , ' of the invention and p--~ii ly when the pul~uA~IJlu~ .l., chains are in the termiDal 20 position, the , are suitable for use in the surfactaDt .~ of the invention and have relatively low cloud points. Cloud points of 1% solutions in water are typically below about 32C and preferably frc~ about 15C to about 30C for optimum control of sudsing throughout a full range of water aDd water l.~u ' 25 t~h~r Sllrf~tsr~tc The , herein can contain other 511rf:~t9-1~C The surfactant can be present in the , in ar~ amount from about 0.1% to about 10%, preferabig from about 0.5% to about 5%, by weight of the Suitable surfactants include anionic surfactants including alkyl sulfonates 30 containing from about 8 to about 20 carbon atoms, alkyl benzene sulfonates containing from about 6 to about 13 carbon atoms in the allcyl group, and the preferred 1~,.. ' mono- and/or diallcyl phenyl oxide mono- and/or di-sulfonates wherein the alkyl groups contain from about 6 to about 16 earbon atoms are also useful in the present invention. All of these anionic surfactants are used as 35 stable salts, preferahly sodium and/or potassium.
Other su~faetants also inelude trialkyl amine oxides, betaines, etc. which are usually high sudsing. A disclosure of bleach-stable surfactants can be found in published British Patent Applieation No. 2,116,199A; U.S. Pat. No. 4,005,027, ~1 7~33S ~ ~ ~

Hartman; U.S. Pat. No. 4,116,851, Rupe et al; and U.S. Pat. No. 4,116,84g, Leikhim, all of which are ill~Ul~f ' herein by reference. Because of the high sudsing, suds ,, ~ VI j discussed l~c~c;lll~clv .. are also preferred.
The preferred surfactants of the invention in f~ ~ with the other 5 ; . of the , provide excellent cleaning and ' 7 p..~ from the standpoint of residual spotting and filming. In these respects, the preferred surfactants of the invenvion provide generally superior r relative to c.I-v7.~ ' nonionic surfactants with llydlv~vlJ;c groups ovher than ' ~dlu~y alcohols and alkyl-phenols, for exarnple, poly~lu~,.e lû oxide or pVI~ulU~l~ ûxide in ~. .l ';~- with diols, triols and other pulJ~,ly~ls or diamines.
Rlf~rh ~
The f o..~ , of the invention optionally contain an amount of bleach sufficient to provide the cf. ~ ;.". with from 0% to about 5%, preferably from about 0.1% to about 5.0%, most preferably from about 0.5% to about 3.0%, of available chlorine or available oxygen based on the weight of the detergent An inorganic chlorine bleach ingredient such as chl ' trisodium phosphate can be utilized, but organic chlorine bleaches such as the l ' u~"~ are preferred. Water-soluble di~ lv~uu~. such as sodium or potassium ~' ' ..;~j dihydrate are p4. i '~, preferred.
The detergent , ' ' according to the present invention can contain bleach , other than the chlorine type. For example, oxygen-type bleaches described in U.S. Pat. No. 4,412,934 (Chung et al), issued Nov. 1, 1983, and peroxyacid bleaches described in European Patent Application û33,2259, Sagel et al, published Sept. 13, 1989, both r ' herein by reference, can be used as a partial or complete lc. ' of the chlorine bleach ingrediem described },~ l~fvlc. These oxygen bleaches are ~iuul~ly preferred when it is desirable to reduce the total chlorine content or use en~yme in the . , of the invention.
Othf~r Optinn ~I Tn,L7r~rliPn~c The automatic d;~h. _ ~ of the invention can optionally contain up to about 50%, preferably from about 2% to about 20%, most preferably less than about 5%, based on the weight of the surfactant, of an alkyl phosphateester suds suppressor.
Suitable alkyl phosphate esters are disclosed in U.S. Patent 3,314,891, issued April 18, 1967, to Schmolka et al, pvld~cd herein by reference.

WO 95/12651 PCT/llS94/11516 ?.~7533S

The preferred alkyl phosphate esters contain from 16-20 carbon atoms.
Highly preferred alkyl phosphate esters are ~ lC/ It~yl acid phosphate or monooleyl acid phosphate, or salts thereof, ~ ul~uly alkali metal salts, or mixtures thereof.
The allcyl phosphate esters have been used to reduce the sudsing of detergent c~ suitable for use in automatic di~l~w~1l;~l6 machines. The esters are J~uli~ul~uly effective for reducing the sudsing of ~ comprising nonionic surfactants which are block polymers of ethylene oxide and propylene oxide.
Filler rnaterials can also be present including sucrose, sucrose esters, sodium 10 chloride, sodium sulfate, potassium chloride, potassium sulfate, etc., in amounts up to about 70%, preferably from 0% to about 40%.
Perfumes (stable as to odor); dyes (such as those disclosed in U.S. Patent 4,714,562, Roselle et al, issued December 22, 1987); and enzymes and crystal modifiers and the like can also be added to the presPnt ~ o~ c in ~
15 amounts. Other commonly used detergent ingredients can also be included.
Additional silicate may also be added to the ~" ~p~ in the form of solid silicate. Preferably, the solid alkali metal silicate is hydrous, having from about 15% io about 25% water, more preferably, from about 17% to about 20%.
The highly alkaline mPt~ cil can be employed, although the less alkaline 20 hydrous alkali metal silicates having a SiO :M O ratio of from about 2.0 to about 2.4 are preferred. Anhydrous forms of the alkali metal silicates with a SiO :M Oratio of 2.0 or more are less preferred because they tend to be ~;6..;rl~l~1y less soluble than the hydrous alkali metal silicates having the same ratio.
Sodium and potassium, and especially sodium, silicates arc preferred. A
25 particularly preferred all~ali metal silicate is a granular hydrous sodium silicate having a SiO :Na O ratio of from 2.0 to 2.4 available from PQ Corporation, named Britesil~) H20 and BritesilE9 H24. Most preferred is a granular hydrous sodium srlicate having a SiO :Na2O ratio of 2Ø
While typical forms, i e. powder and granular, of hydrous silicate particles 30 are suitable, preferred silicate particles have a mean particle size between about 300 and about 900 microns with less than 40% smaller than 150 microns and less than 5% larger than 1700 microns. Pa~ ,ul~ly preferred is a silicate particle with a mean particle size between about 400 and about 700 microns with less than 20%
smaller than 150 microns and less than 1% larger than 1700 microns.

3~ Althou~h some phosphate containing ingredients may be added to the the present invention contains less than about 0.5% phosphate in the form Of l'l'''`IJ ''' The Pr~P~cc W095112651 PCTIUS9~/llS16 ~ 21 7S33S i~ ' ,l ~, Il In step (a), a mixture of 20% to about 90%, preferably from about 40% to about 70%, aqueous aLcali metal silicate solution and from about 5% to about 30%aqueous puly~ J- solution, is spray dried to form free flowing granules.
Applicable spray drying processes are described in U.S. Patents 4,715,979, Moore3 5 et al., issued December 29, 1987, 4,963,226, I'h~rnh~rl -;n et al., issued October 16, 1990 and 4,344,871, Allaway et al., issued August 17, 1982 are il~,UI~ ' ' herein by reference. Other ingredients may optionally be added to the mixture.
Examples of suitable ingredients include alkali metal carbonates (i.e. sodium carbonate), nonionic surfactant, and fillers (i.e. sodium sulfate). Ingredients are 10 selected for this step based upon their stability and safety. Safety protocols should be used to evaluate the ~ y~ explosivity and ~ ;-- potential of the materials used during spray drying.
The next step is to combine the spray dried granules of step (a) with non-phosphate detergency builder (i.e. sodium citrate), and optional ingredients (i.e.
15 low foaming nonionic surfactant and bleaching agent), using any suitable batch or continuous mixing process, so long as a i.~. --,o..l..,- mixture results therefrom.
A preferred ' " is an admixture containing a spray dried ~", ,.l. .~...,-phosphate detergency builder weight ratio of between about 1:20 and about 10:1, l~ih~ly~ more preferably between about 1:12 and about 5:1, most preferably between about 1:3 and about 2:1.
An alternate method, where admixing the ingredients does not yield the desired product bullc densiq, consists of 5L~ the ingredients of step (b) and/or the granules of step (a) with ingredients of step (b). ~g' equipment which facilitates mi~cing and intimate contacting of a liquid binder (preferably ælected from the group consisting of water, solutions of aqueous aL~ali metal salts of poly~ltuAylic acid, liquid silicate, nonionic surfactant and mixtures thereof) with dry detergent ingredients such that it results in agg' granules. Suitable mixing devices include vertical ag~'- (e.g. Schugi Flexomix or Bepex Turboflex ,,,,' ) rotating drums, inclined pan ~ O'Brien mixers, and any other device with suitable means of agitation and liquid spray-on Methods of agitating, mixing, and 5~Lo~ ;,.g particulate . are well-known to those skilled in the art. The apparatus may be designed or adapted for either continuous or batch operation as long as the essential process steps can be achieved.
Once ~' l, the product preferably goes through a " " step (' " g is defined herein as that processing necessary to allow the base granule to come to , ' ' with respect to ~ and moisture content.
This could involve drying off excess water introduced with the liquid binder via WO9S1126S1 217~335 12 PCT/US9.1~11516 suitable drying equipment including fluidized beds, rotary drums, etc. The free moisture content of the base granule should be less than about 10%, preferably less than about 5%. As used herein, free-moisture content is tlrtr-minr'i by placing 5 grams of a sample of base detergent granules in a petri dish, placing the sample in a convection oven at 50C (122F) for 2 hours, followed by - oE the weight loss due to water ~ ... If the liquid binder does not introduce an excess of water, " ~ may involve merely allowing time to reach , ' ' before admixing additional ingredients.
In cases where the c~ contain hydratable salts, it is preferable to 10 hydrate them prior to the ..~cl~ \ step using the hydration process described in, e.g. U.S. Patent No. 4,427,417 issued January 24, 1984 to Porasik, iIIWI,I,)I ' ' h~rein by reference.
After 1~' the final step is to admix the :~c~ l granules with other optional detergent ingredients, such as solid silicate and bleaching agent, 15 using any suitable batch or continuous process as discussed l-~ ,~uv~.
Optional process steps include screening and/or pre-mixing of dry detergent ingredients before -~, cl.. ~ pre-hydration of hydratable salts, and screening and/or grinding of the base granule or final product to any desired particle size.
C~~ ' automatic d;~h~ ' ~ detergent ,~ are preferred 20 herein. C, containing greater than about 60% active ingredients, preferably between about 70% and about 95% active ingredients are preferred.
Preferably, from about 5% to about 98%, most preferably from about 10% to about 50%, of the automatic d;.,t.~h;..g detergent . is detergency builder, and from about 2% to about 80%, preferably from about 20% to about 25 40%, is spray dried granules comprising silicate and water-soluble organic polymer.
As used herein, all p~ parts, and ratios are by weight unless u~h~. w;~: ' The following ' Examples illustrate the process of the invention 30 and facilitate its ~ ' " l,.
FX~MPLF I
The following . ~ are prepared by first forming spray dried granules followed by admixing the remaining dry O " The , are set forth in Table 1.
.Table I
Wt.% ûfDeter~ent Cvl~ ;u W095~12651 21 7533S l PCI/US9~/11516 A
Spray Dried Granule ('o" ,rn~ ~
Sodium ~ly~ yldt~ 4.29 ALkali Metal Silicate 10.26 5Sodium carbonate 14.28 FinAI Product TnE~~ ntc Spray Dried Solid Granule 28.83 Sodium carbonate 14.03 Sodium sulfate 8.23 Sodium citrate 14.28 Nonionic surfactant (1) 3.62 Hydrous sodium silicate (2) 18.16 Bleach 2.65 Water --balance--(1) Blend, by weight of total surfactant, of 38.7% l~u~ul~ydlu~y (C ) alcohol which has been ~LIIu,~y' ' with 8 moles of ethylene oxide per mole of alcohol, 58.1% of polyu,~yl,lul,yl.lle/polyu,.~llyl~.l. reverse block polymer and 3.2% I~uilu~t~uyl~ id phûsphate.
(2) 2.0 ratio SiO2:Na20 Britesil~) H20.
F.XAMPT F :rT
The automatic di~ g detergent ~ .JIlllNJ~ set forth in Table 2 are prepared by (a) spray drying alkali metal silicate and water soluble organic polymer with other . , , (b) ~ AI;~ e and fluid bed drying the spray dried granules with various detergent ingredients and (c) 25 admixing solid silicate and/or bleach.
Table 2 Wt.% of D~trreent Cu..,~
30 B C n Spray DriPA (~IrAn~
Sodium poly~.,ly' 5.56 5.56 5.56 Alkali Metal Silicate 13.30 13.3û 17.88 Sodium carbonate 18.52 9.26 6.17 35Nonionic surfactant(l) 4.78 4.78 Sodium sulfate 10.67 10.67 rvly~ Thickener(2) - 2.00 gJ~lTUTE SHEET (RULE 2b~
, WO95/12651 PCT/US9~/11516 ~
217533~ 14 Fin~l Product ~
SprayDried Solid Granule 37.38 45.57 45.06 Sodium carbonate 9.26 12.35 Sodium sulfate 10.67 - -__ Sodium citrate 18.52 18.52 18.52 Nonionic surfactant (1) 4.78 Liquid silicate 9.94 9.94 10.65 ~m~
Hydrous sodium silicate (3) 5.06 5.06 10 Bleach 3.44 3.44 3.44 Water --------- -- ---Balance---------(I) Blend, by weight of total surfactant, of 38.7% ' ydluAy (C
alcohol which has been ~:,hUA~' ' ' with 8 moles of ethylene oxide per mole of alcohol, 58.1% of pol~u,.~ u~,.yh..~ ,ul~u~ reverse block polymer and 3.2% .nu.~ cid phosphate.
(2) Polygel DK, 3-V Chemical Corporation C3) 2.0 ratio SiO2:Na2O Britesil H20.
The invention may be embodied in other specified forms without departing from the spilit ûr essential . 1 ,.. t . ;`1;~ ` thereof. The present ' ' are 20 therefore to be considered in all respects as illustrative and not restrictive, the scope of the inventiûn being indicated by the appended claims rather ~an by the foregoing ri~crnrtinn and all changes which come within the meaning and range or ~ . v.l~ ..~ of the claims are therefore intended to be embraced therein.
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Claims

1. A process for making high bulk density granular automatic dishwashing detergent composition comprising:
(a) spray drying a mixture comprising from 20% to 90%, by weight of said mixture, of neutralized or alkali metal silicate solution and from 5% to 30%, by weight of said mixture, of water-soluble organic polymer solution to form free flowing granules; and (b) combining from 20% to 80%, by weight of said composition, of said granules of step (a) with from 1% to 90% of a non-phosphate detergent builder, wherein said composition having a bulk density of greater than 0.7 grams/cc and less than 0.5%
phosphate in the form of phosphorous.

2. The process of Claim 1 wherein step (a) comprises from 40% to 70% of said alkali metal silicate solution from 20% to 80% of said non-phosphate detergency builder.

3. The process of Claim 1 or 2 wherein said combining of step (b) is by agglomerating, spray drying, dry mixing or combinations thereof, preferably agglomerating or dry mixing.

4. The process of any one of the preceding claims wherein said detergency builder is selected from the group consisting of water-soluble, alkali metal, ammonium or substituted ammonium carbonates, borates, polyhydroxysulfonates, polyacetates, carboxylates, polycarboxylates and mixtures thereof.
preferably from 15% to 20% sodium carbonate and from 8% to 20% sodium citrate.

5. The process of any one of the preceding claims wherein step (a) further comprises from 0.1% to 10% of a low foaming nonionic surfactant comprising a C16-20 straight chain alcohol condensed with an average of from 6 to 15 moles of ethylene oxide per mole of alcohol, preferably a C18 alcohol condensed with an average of from 7 to 9 moles of ethylene oxide per mole of alcohol.

6. The process of any one of the preceding claims wherein said water-soluble organic polymer of step (a) is selected from the group consisting of aqueous solutions of alkali metal salts of polyacrylates with an average molecular weight in acid form of from 1,000 to 10,000, and acrylate/maleate or acrylate/fumarate copolymers with an average molecular weight in acid form of from 2,000 to 80,000 and a ratio of acrylate to maleate or fumarate segments of from 30:1 to 2:1, and mixtures thereof.

7. The process of any one of the preceding claims wherein said alkali metal silicate solution comprises from 30% to 60% water and said water-soluble organic polymer solution comprises from 10% to 70%
water.

8. The process of any one of the preceding claims further comprising step (c) admixing in an amount of bleach sufficient to provide the composition with 0.1% to 5% of available chlorine or available oxygen based on the weight of the detergent composition preferably the chorine bleach is chlorocyanurate.

9. The process of any one of the preceding claims wherein said alkali metal silicate has a ratio of SiO2:M2O of from 16 to 3.0:1, preferably from 2.0:1 to 2.4:1.wherein M is K+ or Na+ or mixtures thereof.

10. The process of any one of the preceding claims wherein said low foaming nonionic surfactant of step (a) further comprises a polyoxypropylene, polyoxyethylene block polymeric compound and/or from 2% to 20% of an alkyl phosphate ester suds suppressor.

11. The process of any one of the preceding claims wherein said granules of step (a) are agglomerated in step (b) with sald detergency builder and from 3% to 45%, of a liquid binder selected from tbe group consisting of water, aqueous solutions of alkali metal salts of polycarboxylic acid, liquid silicate, nonionic surfactant, and mixtures thereof and wherein in step (b) further comprises anionic surfactants selected from the group consisting of alkyl sulfonates containing from 8 to 20 carbon atoms, alkyl benzene sulfonates containing from 6 to 13 carbon atoms in the carbon atoms in the alkyl group and the mono- and/or dialkyl phenyl oxide, mono and/or di-sulfonates wherein the alkyl groups contain from 6 to 16 carbon atoms, and mixtures thereof

12. The process of any one of the preceding claims wherein from 40% to 70% of said polyoxypropylene, polyoxyethylene block polymeric compound is 75%, by weight of the compound, of a reverse block copolymer of polyoxyethylene and polyoxypropylene containing 17 moles of ethylene oxide and 44 moles of propylene oxide; and 25 %, by weight of the compound, of a block co-polymer of polyoxyethylene and polyoxypropylene, initiated with trimethyl propane, containing 99 moles of propylene oxide and 24 moles of ethylene oxide per mole of trimethylol propane.