CA2207609A1

CA2207609A1 - Liquid laundry detergent

Info

Publication number: CA2207609A1
Application number: CA002207609A
Authority: CA
Inventors: Patrick C. Hu; Eric W. Liimatta
Original assignee: Individual
Current assignee: Albemarle Corp
Priority date: 1994-12-15
Filing date: 1994-12-15
Publication date: 1996-06-20

Abstract

Stable zeolite-containing liquid detergents requiring no viscosity-reducing polymer in order to have a viscosity <= 1000 mPa.s are aqueous surfactant-structured detergents comprising (A) 5-45 % by weight of suspended zeolite particles, (B) 10-30 % by weight of an alkylbenzene sulfonate/nonionic surfactant admixture in which (1) the nonionic component of the admixture is an ethoxylate of an alcohol or an alkylphenol or a mixture thereof with an amine oxide, (2) the alkylbenzene sulfonate/nonionic surfactant weight ratio is in the range of 0.5-10/1, (3) the amine oxide/ethoxylate weight ratio is in the range of 0-4/1, and (4) the amine oxide/alkylbenzene sulfonate weight ratio is in the range of 0-0.5/1, (C) an amount of auxiliary builder in the range of 0.5-4.5 % by weight such that the nonionic surfactant/auxiliary builder weight ratio is not higher than 3.5/1, and (D) 35-80 % by weight of water.

Description

~- r CA 02207609 1997-06-11 LIQUID LAUNDRY DETERGENT

Field of Invention This invention relates to liquid laundry detergents and more particularly relates to such deter~ents cont~ining zeolite builders.

Background It is known that zeolites have been successfully employed as builders in laundrydetergents; and U.S. Patent 4,605,509 (Corkill et al.) discloses commercially attractive detergent powders comprising 5-95% by weight of one or more water-soluble organic surfactants, 5-95% by weight of a zeolite builder, and 5-50% by weight of one or more a~LYiliary builders.
Developing liquid detergents comparable to the detergent powders of Corkill et al. would be desirable. However, in order for them to be commercially attactive, it would be necessary for these liquid detergents to have the zeolite stably suspended therein and to have a maximum viscosity of 1000 mPa s, measured at a shear rate of 21 s-l.
U.S. Patent5,252,244 (Beaujean et al.) teaches aqueous zeolite-cont~iningliquid detergents which are stabilized with an electrolyte s~stem comprising at least one carbonate and at least one sulfate and which have viscosities of 2000-11,000 mPa s (Brookfield viscosimeter, spindle NQ.671O rpm).
As taught in U.S. Patent 5,006,273 (Machin et al.), surfactant structuring--believed to consist of an onion-like configuration comprising concentric bilayers of surfactant molecules having water trapped therebetween--permits solid material to be stably suspended in a liquid detergent. However, surfactant systems such as those of Corkill et al. are frequently incapable of producing a structuring phase for a liquid detergent. Moreover, as disclosed by Machin et al., even surfactant systems suitable for this purpose can create another problem when used in an amount such as to provide asurfactantcontentofatleastlO%byweight: Liquiddetergentscont~iningsuchlarger amounts of surfactant and suspended solids are apt to have viscosities considerably greater than 1000 mPa s unless they also contain a viscosity-reducing polymer.

A~ENDE~ SHEET

~ CA 02207609 1997-06-11 In developingCorkill-likeliquiddetergents havingthe characteristicsmentioned above, i.e., stable suspension of the zeolite and a maximum viscosity of 1000 mPa s, it would be advantageous to be able to avoid having to employ a viscosity-reducing polymer in order to make the detergent pourable; and it would also be desirable for S these liquid detergents to contain less allxili~rybuilder than the Corkill et al. powders.
Having a lower ~n~ rybuilder content would reduce the corrosivity of the deter~ents, lessen detriment to the environment when ecologically-undesirable au~iliary builders are employed, and provide a lower viscosity at any given zeolite level.

Summary of Invention It has been found that li4uid detergents comprising a stable a(lueous suspensionof zeolite particles and having an auxiliary builder content of <5% by weight and a viscosity of <1000 mPa s can be obtained without the use of a viscosity-reducingpolymerwhentheycontaincertainalkylbenzenesulfonate/nonionicethoxylatemixtures as the surfactants.
Thus, the invention resides in an aqueous surfactant-structured liquid detergentcomprising:
(A) 5-45% by weight of suspended zeolite particles, (B) 10-30% by weight of an alkylbenzene sulfonate/nonionic surf~c~nt admixture in which (1) the nonionic component of the ad~ e is an ethoxylate of an alcohol or an alkylphenol, which ethoxylate maybe in ~(lm~ rewith an amine oxide as an optional addition-al ingredient of the nonionic component, (2) the alkylbenzene sulfonate/nonionic snrf~ct~nt weight ratio is in the range of 0.8-5.3/1, (3) the amine oxide/ethoxylate weight ratio is in the range of 0-4/1, and (4) the amine oxide/allylbenzene sulfonate weight ratio is in the range of 0-O.S/1, (C) an amount of ~ rybuilder in the range of 0.545% by weight such that the nonionic surfactant/z~ ry builder weight ratio is not higher than 3.5/1, and (D) 35-80% byweight of water.

AA~tE~lDED S?~

~ CA 02207609 1997-06-11 Detailed Description Like the liquid detergents of Machin et al., the detergent compositions of the invention are aqueous surfactdnt-structured liquid detergents. However, unlike those known liquid detergents, they have the advantages of requiring no viscosity-reducing S polymer in order to have a viscosity of C1000 mPas and of being able to have asuspended particle content as high as 45% by weight--a benefit because of the contribution of zeolite to the cleaning ability of a detergent.
The alkylbenzene sulfonate used dS a component of the surfactant system may be any of the alkylbenzene sulfonates known to be useful as surfactants. However, 10 it is preferably a salt, usually a sodium salt, of an alkylbenzene sulfonate in which the alkyl group contains 10-15, most preferably 11-12 carbons.
As already mentioned, the ethoxylate utilized together with the alkylbenzene sulfonate to provide the surfactant mixture of the novel-compositions may be an ethoxylate of an alcohol or an alkylphenol. Such surfactants are well known and are compounds which usually contain alkyl groups of 8-24 carbons and 4-30 ethoxy groups.
Among the ethoxylates which have been found to be particularly useful in the practice of the invention are the C8-C~6 alcohol ethoxylates containing 4-12 ethoxy (EO) groups per molecule and the octylphenol and nonylphenol ethoxylates containing 6-15 EO
groups per molecule. The ethoxylates of alkylphenols are apt to be ~lefelled when 20 it is important to keep the ~lxili~ry builder content of the compositions particularly low.
The optional amine oxide component of the surfactant may be any of the amine oxides conventionally employed as surfactants, typically an amine oxide corresponding to the formula RR'R"NO in which R is a primary alkyl group cc nt~inin~ 8-24 carbons;
25 R' is methyl, ethyl, or 2-hydroxyethyl; and R" is independently selected from methyl, ethyl, 2-hy~llo~y~thyl, and primary alkyl groups cont~ining 8-24 carbons. Such amine oxides include, e.g., N-octyldimethylamine oxide, N,N-didecylmethylamine oxide, N-decyl-N-dodecylethylamine oxide, N-dodecyldimethylamine oxide, N-tetradecyldimethyl-amine oxide, N-tetradecyl-N-ethylmethylamine oxide, N-tetrddecyl-N-ethyl-2-lly~ y~;lll-30 ylamine oxide, N-h~-Y~1ecyldimethylamine oxide, N-octadecyldimethylamine oxide, N,N-dieicosylethylamine oxide, N-docosyldimethylamine oxide, N-tetracosyldimethylamine AAIENDED S~IEET

~ ' CA 02207609 1997-06-11 ,~ .

oxide, and mi~tures thereof--the preferred amine oxides usually being those containing one long-chain alkyl group, e.g., ~-tetradecyldimethylamine oxide.
When used, the amine oxide may constitute up to 80% of the weight of the nonionic component of the surfactant as long as its concentration is not high enough 5 to provide an amine oxide/allylbenzene sulfonate weight ratio >0.5/1.
The allylbenzene sulfonate/nonionic surfactant proportionations required to provide surfactant structuring of the liquid detergents can vary with the particular ~llxili~ry builder employed and with the concentrations of surfact;mt and ~
builder in the compositions--larger amounts of alkylbenzene sulfonate in the mixtures 10 being utilizable when the compositions have the higher surfactant contents, lower allylbenzenesulfonate/nonionicsurfactantratiosbeingpermissiblewhen the detergents have the higher ~llxili~rybuilder contents, and the range of useful sulfonate/nonionic sur~actant ratios being narrowest at the lowest levels of ~ ry builder. However,in general, the ~ ble allylbenzene sulfonate/nonionic surfactant weight ratios are in the range of 0.8-5.3/1, preferably 1.5~/1, and the ratios best suited for particular compositions within the scope of the invention are easily determined by routine experimentation.
As in Corkill et al., the ~llxili~ry builder may be any of the water-soluble inorganic and organic salts conventionally used in detergent compositions to aid the 20 builder in sequestering "hardness" ions, such as c~lcillm and magnesium ions. Fxt~mrl~ly of such salts are the alkali metal (e.g., sodium and potassium) carbonates,bicarbonates, silicates, chlorides, iodides, citrates, phosphates, pyrophosphates, phosphonates, nitrilotriacetates, polyacrylates, polyaspartates, polycarboxylates, and succinates.
Although, as indicated above, the amount of ~ Ty builder used in the 25 compositions may vary from 0.5-4.5% by weight, the quantity that is preferred in any given instance depends on factors such as the particular surfactant mixture with which it is utilized, the surfactant content of the composition, and the degree to which the auxiliarybuilder might adversely affect the el.vho~ ent. Larger amounts of auxiliary builder are needed when the compositions have the lower surfactant contents, and it 30 appears to be important to employ sufflcient ~llxili~rybuilder to ~l ev~llt the nonionic surfactant/auxiliarybuilder weight ratio from exceeding 3.5/1. However, it is generally AhlE~lD~ S~EET

preferred to utilize~the smaller amounts of au~iliarybuilder (i.e., 0.5-3.5~o by weight) in combinalion with the higher surfactant contents (i.e., 20-30~ by weight) to reduce the corrosivityof the detergents, lessen detrimentto the environmentwhen ecologically-undesirable auxiliarybuilders are employed, and provide a lower viscosity at any given 5 zeolite level.
The particular zeolite employed as a builder in the novel liquid detergents is not critical as long as it is a particulate sodium salt. Thus, although it may be a zeolite of Corkill et al., other zeolites are also utilizable. It is usually a zeolite A or X or mixture thereof, ~referably zeolite A or a zeolite A/zeolite X blend.
In the preparation of the l;quid detergents of the invention, it is not criticalto combine the ingredients in any particular order. However, it is ordinarily preferred to dissolve the water-soluble surfactant ~ e and ~ rybuilder in water to providethe structwing phase before suspending the zeolite particles therein.
The invention is advantageous in its provision of all of its surfactant-structured liquid detergents, but it is particularly beneficial in its permitting the formation of the detergents having surfactant contents of 20-30% and zeolite contents of 15-45%--i.e., those havi~g a compositional makeup which has previously necessitated the use ofviscosity-reducing polymers to make them pourable. The liquid detergents of the invention m ay include minor amounts of additives, such as the dyes, perfumes, enzymes, and preser~vatives frequently used in such compositions; and they could also include the viscosily-reducing polymers of known Iiquid detergents without losing their surfactant ~tructuring. However, it is unlikely that it would ever be really desirable to incorpor'3te viscosity-reducing polymers: They would be unnecessary and therefore would merely add to the cost of the d~Lc;l~,ellL~.
The Eollowing examples are given to illustrate the invention and are not intended as a limitationtherof. Unless otherwise specified, quantitiesmentionedin the examples are quantit~es by weight, and codes are used to represent detelgellt ingredients as indicated below.

AMEND~D S~IEET

' CA 02207609 1997-06-11 - Code Ingredient S-l Sodium citrate S-2 Sodium carbonate LAS Sodium dodecylbenzene sulfonate S AS Sodium Cl2-Cls allyl sulfate AES Sodium lauryl ether sulfate containing three EO (-OCH2CH2-) groups per molecule AE A 7-EO ethoxylate of a mixture of Cl2-Cl4 alcohols NPE l~he 9-EO etho~ylate of nonylphenol Prepare a series of base compositions to determine their ability to serve as the structuring phases of zeolite-containing liquid detergents. The ingredients used and the amounts employed are shown in Table I.
TABLE I
Composition ¦ LAS ¦ AS ¦ AES ¦ AE ¦ NPE ¦ S-l ¦ S-2 ¦ Water Part A - Base Compositions of Il~v~ ion G 18 -- -- 12 -- -- 4.165.9 Part B - Cu~ liv~ Base Compositions B-l -- 14 -- 6 -- 4 -- 76 C-l -- 14 -- 6 -- 7 -- 73 E-l -- 14 -- -- 6 5 -- 75 AME1~1DED SHEET

CA 02207609 1997-06-ll TABLEI-Pa~ B (Gont~ued) F 14 -~ 6 7 -- 73 F-l 14 6 7 -- 73 H-l 8 -- -- 12 -- 5 -- 75 I-l 8 -- -- -- 12 6 -- 74 Test each of the base compositions of Example 1 for ability to seIve ~s a structuringphaseby(1)stirringzeoliteparticlesthereintoformasuspensioncontaining 10-15~o byweight of suspended zeolite, (2) storing the suspension at room temperature, 15 and (3) ex~mining the suspension after two months to determine its stability. The test shows that each of the suspensions made from a base composition within the scopeof the invention or from any of the comparacive compositions having an alphabetic designation with no numeric suffix is stable, whereas there is appreciable settling of the zeolite from each of the other comparative base compositions to form a second 20 phase.

As demonstrated above, the use of selected allylbenzene sulfonate/nonionic etho~ylate ll~Lules as the s~ ct~nt~ has the unexpected result of providin~ a sllrf~rt~nt structuring of zeolite-containing liquid detergents that is not obtained when they are replaced with surfactant llli~sLulc;S which are norrnally considered equivalent thereto.
~5 This phenomenon is also observed when a portion of the ethoxylate is replaced with an amine oxide and/or larger amounts of zeolite are suspended in the base compositions to form other liquid detergents having viscosities ~1000 mPa s and zeolite contents as high as 45% by weight.

A~1EN~ED SHE~

Claims

1. An aqueous surfactant-structured liquid detergent comprising (A) 5-45%
by weight of suspended zeolite particles, (B) 10-30% by weight of an alkylbenzene sulfonate/nonionic surfactant admixture in which (1) the nonionic component of the admixture is an ethoxylate of an alcohol or an alkylphenol, which ethoxylate may be in admixture with an amine oxide as an optional additional ingredient of the nonionic component, (2) the alkylbenzene sulfonate/nonionic surfactant weight ratio is in the range of 0.8-5.3/1, (3) the amine oxide/ethoxylate weight ratio is in the range of 0-4/1, and (4) the amine oxide/alkylbenzene sulfonate weight ratio is in the range of 0-0.5/1, (C) an amount of auxiliary builder in the range of 0.5-4.5% by weight such that the nonionic surfactant/auxiliary builder weight ratio is not higher than 3.5/1, and (D) 35-80% by weight of water.

2. The liquid detergent of claim 1 having a viscosity ~1000 mPa-s.

3. The liquid detergent of claim 1 wherein the alkylbenzene sulfonate/nonionic surfactant weight ratio is in the range of 1.54/1.

4. The liquid detergent of claim 1 wherein the alkylbenzene sulfonate is a salt of an alkylbenzene sulfonate in which the alkyl group contains 10-15 carbons.

5. The liquid detergent of claim 4 wherein the alkylbenzene sulfonate is a sodium salt of an alkylbenzene sulfonate in which the alkyl group contains 11-12carbons.

6. The liquid detergent of claim 1 wherein the ethoxylate contains 4-30 ethoxy groups and is an ethoxylate of one or more alcohols containing 8-24 carbons.

7. The liquid detergent of claim 6 wherein the ethoxylate is a C8-C16 alcohol ethoxylate containing 4-12 ethoxy groups per molecule.

8. The liquid detergent of claim 1 wherein the ethoxylate contains 4-30 ethoxy groups and is an ethoxylate of an alkylphenol in which the alkyl group contains 8-24 carbons.

9. The liquid detergent of claim 8 wherein the ethoxylate is an octylphenol or nonylphenol ethoxylate containing 6-15 ethoxy groups per molecule.

10. The liquid detergent of claim 1 wherein the ethoxylate is the sole nonionic component of the surfactant admixture.

11. The liquid detergent of claim 1 wherein the nonionic component of the surfactant admixture is a mixture of the ethoxylate and an amine oxide.

12. The liquid detergent of claim 11 wherein the amine oxide is a compound corresponding to the formula RR'R"NO in which R is a primary alkyl group containing 8-24 carbons; R' is methyl, ethyl, or 2-hydroxyethyl; and R" is independently selected from methyl, ethyl, 2-hydroxyethyl, and primary alkyl groups containing 8-24 carbons.

13. The liquid detergent of claim 1 wherein the auxiliary builder is sodium citrate.

14. The liquid detergent of claim 13 having a viscosity ~ 1000 mPas, a suspended zeolite content of 15-45% by weight, a surfactant mixture content of 20-30%
by weight, an alkylbenzene sulfonate/nonionic surfactant weight ratio in the range of 1.5-4/1, and a sodium citrate content of 0.5-3.5% by weight.

15. The liquid detergent of claim 14 wherein the surfactant is a mixture of (A) a sodium salt of an alkylbenzene sulfonate in which the alkyl group contains 11-12 carbons and (B) an octylphenol or nonylphenol ethoxylate containing 6-15 ethoxy groups per molecule.

16. The liquid detergent of claim 1 wherein the auxiliary builder is sodium carbonate.

17. The liquid detergent of claim 16 having a viscosity ~ 1000 mPa-s, a suspended zeolite content of 15-45% by weight, a surfactant mixture content of 20-30%
by weight, an alkylbenzene sulfonate/nonionic surfactant weight ratio in the range of 1.5-4/1, and a sodium carbonate content of 0.5-3.5% by weight.

18. The liquid detergent of claim 17 wherein the surfactant is a mixture of (A) a sodium salt of an alkylbenzene sulfonate in which the alkyl group contains 11-12 carbons and (B) an octylphenol or nonylphenol ethoxylate containing 6-15 ethoxy groups per molecule.