WO1996018713A1

WO1996018713A1 - Liquid laundry detergent

Info

Publication number: WO1996018713A1
Application number: PCT/US1994/014421
Authority: WO
Inventors: Patrick C. Hu; Eric W. Liimatta
Original assignee: Albemarle Corporation
Priority date: 1994-12-15
Filing date: 1994-12-15
Publication date: 1996-06-20
Also published as: JPH10510857A; EP0797654B1; DE69424319D1; DE69424319T2; EP0797654A1

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

LIQUID LAUNDRY DETERGENT

Field of Invention

This invention relates to liquid laundry detergents and more particularly relates to such detergents containing zeolite builders.

Background

It is known that zeolites have been successfully employed as builders in laundry detergents; 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 auxiliary 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"¹. U.S. Patent 5,252,244 (Beaujean et al.) teaches aqueous zeolite-containing liquid detergents which are stabilized with an electrolyte system comprising at least one carbonate and at least one sulfate and which have viscosities of 2000-11,000 mPa-s (Brookfield viscosimeter, spindle No. 6, 10 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 a surfactant content of at least 10% by weight: Liquid detergents containing such larger 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.

In developing Corkill-like liquid detergents having the characteristics mentioned 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 these liquid detergents to contain less auxiliary builder than the Corkill et al. powders. Having a lower auxiliary builder content would reduce the corrosivity of the detergents, lessen detriment to the environment when ecologically-undesirable auxiliary builders are employed, and provide a lower viscosity at any given zeolite level.

Summary of Invention

It has been found that liquid detergents comprising a stable aqueous suspension of 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-reducing polymer when they contain certain alkylbenzene sulfonate/nonionic ethoxylate mixtures as the surfactants.

Thus, the invention resides in 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 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.

Detailed Description Like the liquid detergents of Machin et al. (the teachings of which are incorporated herein by reference), the detergent compositions of the invention are aqueous surfactant- structured liquid detergents. However, unlike those known liquid detergents, they have the advantages of requiring no viscosity-reducing polymer in order to have a viscosity of < 1000 mPa-s and of being able to have a suspended 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 as a component of the surfactant system may be any of the alkylbenzene sulfonates known to be useful as surfactants. However, 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-C₁₆ 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 preferred when it is important to keep the auxiliary 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 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. Such amine oxides include, e.g., N-octyldimemylamine oxide, N,N-didecyimethylaπιine oxide, N-decyl- N-dodecylethylamine oxide, N-dodecyldimethylamine oxide, N-tetradecyldimethylamine oxide, N-tetradecyl-N-emylmemylamine oxide, N-tetradecyl-N-€myl-2-hydroxyemylamine oxide, N-hexadecyldimethylamine oxide, N-octadecyldimethylamine oxide, N,N- dieicosylethylamine oxide, N-docosyldimethylamine oxide, N-tetracosyldimethylamine oxide, and mixtures thereof — the preferred amine oxides usually being those containing one long-chain alkyl group, e.g. , N-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 to provide an amine oxide/alkylbenzene sulfonate weight ratio > 0.5/1. The alkylbenzene sulfonate/nonionic surfactant proportionations required to provide surfactant structuring of the liquid detergents can vary with the particular auxiliary builder employed and with the concentrations of surfactant and auxiliary builder in the compositions — larger amounts of alkylbenzene sulfonate in the mixtures being utilizable when the compositions have the higher surfactant contents, lower alkylbenzene sulfonate/nonionic surfactant ratios being permissible when the detergents have the higher auxiliary builder contents, and the range of useful sulfonate/nonionic surfactant ratios being narrowest at the lowest levels of auxiliary builder. However, in general, the utilizable alkylbenzene sulfonate/nonionic surfactant weight ratios are in the range of -0.5-10/1, preferably -0.8- 5.3/1, more preferably - 1.5-4/1, 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 teachings of which are incorporated herein by reference), the auxiliary builder may be any of the water-soluble inorganic and organic salts conventionally used in detergent compositions to aid the builder in sequestering "hardness" ions, such as calcium and magnesium ions. Exemplary 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 auxiliary builder used in the 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 auxiliary builder might adversely affect the environment. Larger amounts of auxiliary builder are needed when the compositions have the lower surfactant contents, and it appears to be important to employ sufficient auxiliary builder to prevent the nonionic surfactant/ auxiliary builder weight ratio from exceeding -3.5/1. However, it is generally preferred to utilize the smaller amounts of auxiliary builder (i.e. , 0.5-3.5% by weight) in combination with the higher surfactant contents (i.e., 20-30% by weight) to reduce the corrosivity of the detergents, lessen detriment to the environment when ecologically-undesirable auxiliary builders are employed, and provide a lower viscosity at any given zeolite level.

The particular zeolite employed as a builder in the novel liquid detergents is not critical as long as it is a paniculate 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, preferably zeolite A or a zeolite A/zeolite X blend.

In the preparation of the liquid detergents of the invention, it is not critical to combine the ingredients in any particular order. However, it is ordinarily preferred to dissolve the water-soluble surfactant mixture and auxiliary builder in water to provide the structuring 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 having a compositional makeup which has previously necessitated the use of viscosity-reducing polymers to make them pourable. The liquid detergents of the invention may include minor amounts of additives, such as the dyes, perfumes, enzymes, and preservatives frequently used in such compositions; and they could also include the viscosity-reducing polymers of known liquid detergents without losing their surfactant structuring. However, it is unlikely that it would ever be really desirable to incorporate viscosity-reducing polymers:

They would be unnecessary and therefore would merely add to the cost of the detergents.

The following examples are given to illustrate the invention and are not intended as a limitation therof . Unless otherwise specified, quantities mentioned in the examples are quantities by weight, and codes are used to represent detergent ingredients as indicated below. Code Ingredient

S-l Sodium citrate

S-2 Sodium carbonate

LAS Sodium dodecylbenzene sulfonate

AS Sodium C₁₂-C₁₅ alkyl sulfate

AES Sodium lauryl ether sulfate containing three EO (- OCH₂CH₂-) groups per molecule

AE A 7-EO ethoxylate of a mixture of C₁₂-C₁₄ alco¬ hols

NPE The 9-EO ethoxylate of nonylphenol

EXAMPLE 1 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

A 7 - - 3 — 5 ~ 85

B 14 - - 6 — 4 « 76

B-l - 14 - 6 ~ 4 - 76

B-2 — - 14 6 — 4 - 76

C 14 - — 6 ~ 7 - 73

C-l - 14 - 6 - 7 - 73

C-2 - - 14 6 - 7 - 73

D 14 - ~ - 6 3 - 77

E 14 - - - 6 5 - 75

E-l - 14 ~ - 6 5 - 75

E-2 — - 14 - 6 5 ~ 75

F 14 - - - 6 7 - 73

F-l — 14 - ~ 6 7 ~ 73

F-2 - - 14 - 6 7 ~ 73 TABLE I (continued)

G 18 — — 12 — — 4.1 65.9

H-l 8 — - 12 — 5 — 75

H-2 — 8 — 12 ~ 5 ~ 75

H-3 — — 8 12 ~ 5 — 75

1-1 8 — — — 12 6 ~ 74

1-2 — 8 ~ - 12 6 — 74

1-3 ~ ~ 8 - 12 6 ~ 74

EXAMPLE 2 Test each of the base compositions of Example 1 for ability to serve as a structuring phase by (1) stirring zeolite particles therein to form a suspension containing 10-15% by weight of suspended zeolite, (2) storing the suspension at room temperature, and (3) examining the suspension after two months to determine its stability. The test shows that each of the suspensions made from a base composition within the scope of the invention (i.e., the compositions having an alphabetic designation with no numeric suffix) is stable, whereas there is appreciable settling of the zeolite from each of the comparative base compositions to form a second phase.

As demonstrated above, the use of selected alkylbenzene sulfonate/nonionic ethoxylate mixtures as the surfactants has the unexpected result of providing a surfactant structuring of zeolite-containing liquid detergents that is not obtained when they are replaced with surfactant mixtures which are normally considered equivalent thereto. 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.

Claims

WHAT IS CLAIMED IS:

1. An aqueous surfactant-stπ-inured liquid detergent compή-ang (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 surfac- tant/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 -1.5-4/1.

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 11-12 carbons.

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

7. The liquid detergent of claim 6 wherein the ethoxylate is a C,-C,₆ 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 octyiphenol 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-hydroxyeιhyl, 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 < 1 00 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 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 octyiphenol or nonylphenol ethoxylate ∞ntaining 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 octyiphenol or nonylphenol ethoxylate containing 6-15 ethoxy groups per molecule.