CA1269012A - Liquid laundry detergent composition - Google Patents

Abstract

ABSTRACT OF THE INVENTION
A liquid heavy duty laundry detergent composition comprising a suspension of a builder salt in a liquid nonionic surfactant, said composition containing also a compound comprising a polyether nonionic surfactant which has an ester linkage between a polyether group and a group having a free COOH.

Description

~L2~
This application is a divisional of Application No.
478,379 filed on April 4, 1985.
The invention of the parent application relates to a liquid heavy duty laundry detergent composition comprising a suspension of builder salt in a liquid nonionic surfactant, said composition containing sufficient polyether carboxylic acid wherein an ester linkage is attached to a polyether group to decrease the temperature at which said surfactant forms a gel with water.
This divisional application relates to a liquid heavy duty laundry detergent composition comprising a suspension of a builder salt in a liquid nonionic surfactantl said composition containing also a compound comprising a polyether nonionic surfactant which has an ester linkage between a polyether group and a group having a free COOH.
A second divisional application relates to a half ester of (a) a nonionic surfactant which is a polyalkoxylated higher alkanol and ~b) a dicarboxylic acid.
Liquid nonaqueous heavy duty laundry detergent compositions are well ~nown in the art. For instance, compositions of that type may comprise a liquid nonionlc surfactant in which are dispersed particles of a builder, as shown for instance in the United States patents Nos. 4,316,812;
3,630,929; 4,264,466, and British patents Nos. 1,205,711 and 1,270,040.
In the ordinary use of European household automatic washing machines, the user places the laundry detergent composition in a dispensing unit (e.g., a dispensing drawer) of the machine. Then during the operation of the machine, the detergent in a dispenser is subjected to a stream of cold water to transfer it to the main body of wash solutions. In winter, ~ 2~ ~f~ ~ 62301-1309D

when the detergent composition and the water fed to the dispenser are cold, there can be problems in that some of the composition is not flushed completely off the dispenser during operation of the machine, and a deposit of the composition builds up with repeated wash cycles, so that it may become necessary for the user to flush the dispenser with hot water.
One reason for this problem involves the behaviour of the nonionic surfactant when mixed with cold water. Its viscosity increases markedly and a gel is formed. As a result, the detergent composition does not flow readily or completely from the dispenser.
It has now been found that the flow from the di~pen~er can be improved considerably by including in the liquid detergent composition sufficient polyether carboxylic acid wherein an ester linkage is attached to a polyether group to decrease the temperature at which the suractant Eorms a gel wlth water. Such a compound may be formed, for instance, by reacting a nonionic surfactant with a polycarboxylic acid anhydride, such as succinic anhydride, to form a partial ester of the polycarboxylic acid. The resulting acidic compound will react, in the wash bath, with the alkalinity of the detergent composition and acts as an effective anionic surfactant.
Preferably the polyether carboxylic acid is soluble in the nonionic surfactant and the composition is substantially nonaqueous.
A preferred embodiment of the other divisional appli-cation provides a half ester o (a) a nonionic surfactant which i~ a polyoxyethylated higher alkanol and (b) a dicarboxylic acid.
The inventions of this application and the divisional applications are illustrated further by the following examples:

~Z69~i 2 400 g. of a nonionic surfactant which is a C13 to C15 alkanol which has been alkoxylated to introduce 6 ethylene oxide and 3 propylene oxide units per alkanol unit is mixed with 32 g. of succinic anhydride and heated for 7 hours at 100C. The mixture is then cooled and filtered to remove unreacted succinic materi.al. Infrared analysis indicates that about one half of the nonionic surfactant has been converted to the acidic half ester thereof. Viscosities and gel tempera-tures of the product as compared to the unmodlfied nonionic ~urfactant are given below:

lZ69~

Product Unmodified Nonionic Surfactant_ Viscoslty at 20C 138 cps 60 cps Cel temperature of a 40/60 mlxture wlth water (l.e. mlxture con-talnlng 60Z water) 7C 20C

Vl~co~ity of the 40/60 mlxture wlth water at 25C 60 cp~ 189 cps at 20C 100 cps 445 cp~

It will be ~een that even though the product (which, au previou~ly lndica~ed, 1~ a mlxture of about equal parts of un~odlf~ed nonionic surfactant and acidic half ester thereof) ha~ a hlgher vlscoslty than the unmodifled ~urfactant, its vlscosity on dllution with wster i~ conslderably lower, a~ is lt~ gelllng temperature.

_AMPLE 2 522 g. of the nonlonic fiurfactant known as Dobanol*
25-7 (the product of ethoxylation of a C12 to C15 alkanol, whlch protuct has about 7 ethyleneoxlde units per molecule of slkanol2 iB m$xed with 100 g. of ~uccinic anhydrlde and 0.1 g.
of pyrldine (which acts as an e~terification catalyst here~ and heated at 60C for 2 hour~, cooled and filtered to remove un-reacted succlnic materlal. Infrared analy~is indlcates that ~ubstsntlally all the free hytroxyls of the surfactant have re-acted.
Other e~teriflcation catalyst~, such a8 an alksli metal slkoxlde (e.g. ~odlum methoxide) may be used ln place of, or in admlxture with, the pyrldine.

* Trademark $~ -Exsmple 2 is repeated using 1000 g. of Dobanol*91-5 ~the product of ethoxylation of a Cg to Cll alkanol, which product haR about 5 ethylene oxlde units per molecule of alkanol) and 265 g. succin~c anhydrlde.

A llquld nonsqueou6 heavy duty laundry detergent i6 formulated from the following ingredients, ln the proportlons ~peclfled.
3SX nonlonlc surfactant comprlslng a mlxture of equal part~ of:
(8) a relatlvely water ~oluble nonionlc ~urfactant whlch form3 a gel wnen mixed wlth water at 25~C, ~peclfically a C13 to ClS alkanol whlch has been alkoxylated to lntroduce 10 ethylene oxlde and 5 propylene oxlde unlts per alkanol unlt and (b) a less water-~oluble nonionlc ~urfactant, ~peciflc-ally a C13 to C15 alksnol whlch has been alkoxylated to lntroduce 4 ethylene oxlde and 7 propylene oxlde unlt6 per alkanol unlt.
12% of the product of Example 3.
31.2% sodium tripolypho~phate.
9X 60dlu~ perborate monohydrate.
4.5% tetraacetyl ethylene diamine; thi~ 18 an activator for the sotium perborate.
4Z copolymer of about equal molee of methacrylic acld and malelc anhydride, completely neutrallzed to form the sodium sslt thereof (Sokalan*CP5); thl~ serve~ to inhlblt lncru~tatlon (-B from formation of dlcalcium phosphate).

* Trademark --lZ sodium salt of diethylene triamine p~ntamethylene pho~phonic acid (DTP~P), 1% Proteolytlc enzyme slur~y ~in non~onic surfactant) (Esperase) lX mixture of sodium carboxymet~ylcellulose and hydroxymethylcelluloqe ~an antiredeposition agent) (Relatin*
DM4096).
0.5% perfume 0.5% opticnl brightener (of stilbene 4 type) 0.3% partial ester of phoephorlc acld and a C16 to C18 alkanol (Empiphos*5632, ln which there is about 1/3 monoester and

2/3 die~ter) The ingredientfi are mlxed together, w$th the phosphoric ester and then the ~odium tripolyphosphate belng preferably added last, and pas~ed through a collold mill to reduce the particle size of the ~olld materials to le&s than 100 microns ~e.g. to about 40 microsn). The mixture is then sub~ected to ginding to reduce the ~izes of the suspended ~olid partlclee to lesa thsn 10 mlcrons (e.g. to in the range of abou~ 2 to lO microns wlth less than about 10% of the solids hsving psrtlcle size8 sbove sbout 10 microns).
The ingredlents and conditions are chosen so that the total unbound water content of the compoeition iB leea than 2%, preferably less than lX, such as about ~% or les~.

* Trademark ~2~ 62301-1309D

The mixture has a high viscosity, but dispenses readily with cold water in the automatic washing machine. Its specific gravity is about 1.25. It gives excellent washing when used at a dosage of about 100 grams per wash load (as compared with 170 grams per wash load for the usual heavy duty laundry detergent powders) in conventional European home laundry machines (which employ ahout 20 liters of water for the washing hath~.
In the foregoing Examples/ there is a carboxylic acid moiety joined to the residue of the nonionic surfactant by a carboxylic ester linkage. Instead of a succinic acid moiety, othex polycarboxylic acid moieties may be used, e.g., maleic, glutaric, malonic, phthalic, citric, etc. Other linkages may be used, such as ether, thioether or urethane linkages, formed by conventional reactions. For instance, to form an ether linkage, the nonionlc surfactant may be treated with a strong ~ase (to convert its OH group to an ONa group for instance) and then reacted with a halocarboxylic acid such as chloroacetic acid or chloropropionic acid or the corresponding bromo compound.
Thus the resulting carboxylic acid may have the formula R-Y-ZCOOH where R is the residue of a nonlonic surfactant (on removal of a terminal OH), Y is oxygen or sulfur and Z
represents an organic linkage such as a hydrocarbon group of say, one to ten carbon atoms which may be attached to the oxygen (or sulfur) of the formula directly or by means of an intervening linkage such as an oxygen-containing linkage, e.g.,a C O
Il 11 -C- or -C-NH-, (i.e., carbonyl or carboximido, respectively).

The carboxylic acid may be produced from a polyether :30 which is not a nonionic surfactant, e.g., it may be made by reaction with a polyalkoxy compound such as polyethylene glycol ;5 or a monoester ~ monoether thereof which does not have the long alkyl chain characteristic of the nonionic surfactants. Thus, R may have the formula R (OCH-CH2)n - where R is hydrogen or methyl, Rl is alkylphenyl or alkyl or other chain terminating group and "n" is at least 3 such as 5 to 25. When the alkyl of Rl is a higher alkyl, R is a residue of a nonionic surfactant.
~s indlcated above Rl may instead be hydrogen or lower alkyl (e.g., methyl, ethyl, propyl, butyl) or lower acyl (e.g., acetyl, etc.). The acidic polyether compound is preferably present, in the detergent composition, as a solution in the nonionic surfactant.
The carboxylic used may also be a polyalkoxy-carboxylate or N-acyl sarcosinate as described and listed in Kirk-Othmer, "Encyclopedia of Chemical Technology", 3rd Edition, Vol. 22 (1983), Pages 348-349.
As is ~ell known, the nonionic synthetic organic detergents are characterized by the presence of an organic hydrophobic group and an organic hydrophilic group and are typically produced by the condensation of an organic aliphatic or alkyl aromatic hydrophobic compound with ethylene oxide (hydrophilic in nature). Practically any hydrophobic compound having a carboxy, hydroxy, amido or amino group with a free hydrogen attached to the nitrogen can be condensed with ethylene ox~de or with the polyhydration product thereof, polyethylene glycol, to form a nonionic detergent. The length of the hydrophilic or polyoxy ethylene chain can be readily adjusted to achieve the desired balance between the hydrophobic and hydrophilic groups. Typical suitable nonionic surfactants are those disclosed in United States patents 4,316,812 and ~LZ6~ 6 2 301 -1 3 0 9D

3,630,929, as well as those described and listed in the discussion on nonionic surfactants in Kirk-Othmer "Encyclopedia of Chemical Technology",3rd Edition, Vol. 22 (1983), Pages 360-379.
The compositions preferably contain fine particles of a detergent builder dispersed in the nonionic surfactant.
Among the suitable builders are inorganic and organic builder salts such as the phosphates, carbonates, silicates, phosphonates, polyhydroxysulfonates, polycarboxylates and the like. Typical suitable builders are those disclosed in United States patents 4,316,812; 4,264,466; and 3,630,929.
Since, as indicated in Example 4, the compositions may be used at relatively low dosages, it is desirable to supplement any phosphate builder (such as sodium tripoly-phosphate) with an auxiliary builder such as a polymeric carboxylic acid having high calcium binding capacity, in amount in the range, for instance, of about 1 to 10% of the composition, to inhibit incrustation which could otherwise be caused by formation of an insoluble calcium phosphate. Such auxiliary builders are well known in the art.
The composition preferably compri~es a psroxygen bleaching agent. This may be a peroxygen compound, such as an alkali metal perborate, percarbonate or perphosphate; a particularly suitable material is sodium perborate monohydrate.
The peroxygen compound is preferably used in admixture with an activator therefor. Suitable activators are those disclosed in United States patent 4,264,466 or in column 1 of United States patent 4,430,244~ Polyacylated compounds are _ g _ ~L2G~2 preferred activators; among ehese, co~pounds such as tetraacetyl ethylene diamlne ("TAED") and pentaacetyl glucose are part~cularly ~referred.
The activator usually interacts with the peroxygen compound to form a peroxyacld bleaching agent in the wash water.
It i8 preferred to lnclude a sequestering agent of high complexing power to lnhlblt any unde~ired reaction between such peroxyscld and hydrogen peroxlde in the wash solution in the presence of metal ions. Such a seque~tering agent ls an organic compound whlch 1~ able to form a complex with Cu2+ ion6, ~uch that the 8tablllty con~tant (pK) of the complexation ls equal to or greater than 6, at 25C, in water, of an ionic strength of 0.1 molelliter, pK belng conventionally defined by the formula: pK~-log K where K repre~ents the equllibrium constant. Thus, for example, the pK values for complexatlon of copper ion with NTA and EDTA at the ~tated condltions are lZ.7 and 18.8, respectlvely. Suitable ~equestering agents include the sodium ~alts of nitrilotriacetic scid (NTA); ethylene dlamine tetraacetlc acid (EDTA); diethylene trlsmine pentaacetlc acid (DETPA); diethylene triamlne penta-~thylene phocphonic acid (DTPMP); and ethylene dlamine tetrs-methylene phosphonic acit ~EDITEMPA).
Other ingredients which may be included in the compo-~ltlon are enzymes (e.g. protea~e~, amylases or l$pases or mixturec thereof), optical brightener~, antiredepositlon agents, colorante (e.g. pigment~ or dye~) etc.

~26~ 62301-1309D

The composition may also contain an inorganic insoluble thickening agent or dispersant of very high surface area such as finely divided silica o~ extremely fine particle size le.g., of 5-100 millimicrons diameter such as sold under the name Aerosil*) or the other highly voluminous inorganic carrier materials disclosed in United States patent 3,630~929, in proportions of 0.1-10%, e.g., 1 to 5%. It is preferable, however, that compositions which form peroxyacids in the wash bath (e.g., compositions containing peroxygen compound and activator therefor) be substantially free of such compounds and of other silicates; lt has been found, for instance, that 6ilica and silicates promote the undesired decomposition of the peroxyacid.
Preferably the mixture of liquid nonionic surfactant and solid ingredients is subjected to an attrition type of mill in which the particle sizes of the solid ingredients are reduced to less than about 10 microns, e.g., to an average particle size of 2 to 10 microns or even lower (e.g., 1 micron).
Compositions whose dispersed particles are of such small size have improved stability against separation or settling on storage. It is found that the acidic polyether compound can decrease the yield stress of such dispersions, aiding in their dispensibility, without a corresponding decrease in their stability against settling.
l'he mixture may contain anti-settling ingredients such as a partial ester of phosphoric acid and a higher alkanol, present in small amounts such as less than 1%, e.g., below 1/2%, during the grinding. Other phosphate ester surfactants may be used instead such as those described and listed in Kirk-Othmer "Encyclopedia of Chemical Technology", 3rd Edition, Vol. 22(1983), Pages 359-361.

*Trade Mark ~g~6~3~ ~ 2 In the grinding operation it is preferred that the proportion of solid ingredients be high enough (e.g., at least about 40% such as about 50%) that the solid particles are in contact with each other and are not substantially shielded from one another by the nonionic surfactant liquid. Mills which employ grinding balls (ball mills) or similar mobile grinding elements have given very good results. Thus, one may use a laboratory batch attritor having 8 mm diameter steatite grind-ing balls. For larger scale work a continuously operating mill in which there are 1 mm or 1.5 mm diameter grinding balls working in a very small gap between a stator and a rotor operating at a relatively high speed (e.g., a CoBall mill) may b~ employed; when using such a mill, it is desirable to pass the blend of nonionic surfactant and solids first through a mill which does not effect such fine grinding (e.g., a colloid mill) to reduce the particle size to less than 100 microns (e.g., to abo~t 40 microns) prior to the step of grinding to an average particle diameter below about 10 microns in the continuous ball mill.
In the compositions typical proportions of the ingredients are as follows:
Suspended detergent builder, within the range of about 10 to 60~ such as about 20 to 50%, e.g., about 25 to 40%;
li~uid phase comprising nonionic surfactants and dissolved carboxylic acid gel-inhibiting compound, within the range of about 30 to 70%, such as about 40 to 60%; this phase may also lnclude a diluent such as a glycol, e.g., polyethylene glycol (e.g., "PEG 400") or hexylene glycol.

` - -6~

Carboxylic ac$d gel-inhibit~ng compound, an amount to ~upply ln the range of about 0.5 to 10 part~ (e.g., about 1 to 6 part# ~uch as about 2 to 5 parts) of -COOH (M.W. 45) per 100 part~ of blend of such acid compound and nonionlc ~urfact-ant. (In Example 4 there are about 3 part~ of COOH per 100 psrts of such blend). Typlcally, the amount of the carboxyllc acld compound 18 in the ran8e of about 0.01 to 1 part per part of nonlolc surfactant, such as about 0.05 to 0.6 part, e.g., sbout 0.2 to 0.5 part;
Peroxygen compound (such as sodium perborate monohydrate) ln the ran8e of about 2 to 15%, such as about 4 to 10%;
Acti~ator, ln the range of about 1 to 8%, such a6 about 3 to 6%.
A sequestering agent of high complexing power, in the rsnge o sbour ~ to 3%, 8UC~ as about ~ to 2%.
In this application all proportlons are by welght un-le~ other wlse indlcated. In the Examples, atmospherlc pre~-uure is used unless other wl~e indlcated.
It is understood that the foregoing detailed descrlptlon 18 given merely by way of illustration and that variatlons may be ~ade thereln without departlng irom the spirlt o f the inventlon.

_ 13 ~

Claims (8)

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

1. A liquid heavy duty laundry detergent composition comprising a suspension of a builder salt in a liquid nonionic surfactant, said composition containing also a compound comprising a polyether nonionic surfactant which has an ester linkage between a polyether group and a group having a free COOH.

2. A composition according to claim 1 in which said compound is a partial ester of a nonionic surfactant and a polycarboxylic acid.

3. A composition according to claim 2 in which said polycarboxylic acid is succinic acid.

4. A composition according to claim 2 in which said compound is a partial ester of a polycarboxylic acid and a polyethoxylated higher alkanol.

5. A composition according to claim 1 in which said builder salt is an alkali metal polyphosphate.

6. A composition according to claim 1 containing also suspended peroxygen bleaching agent.

7. A composition according to claim 6 in which said bleaching agent comprises sodium perborate monohydrate and an activator therefor.

8. A composition according to claim 6 in which said activator comprises tetraacetyl ethylene diamine.