EP0206375A1

EP0206375A1 - Liquid cleaning and softening compositions

Info

Publication number: EP0206375A1
Application number: EP86200859A
Authority: EP
Inventors: Tan Tai Dr. Ho
Original assignee: Unilever PLC; Unilever NV
Current assignee: Unilever PLC; Unilever NV
Priority date: 1985-05-28
Filing date: 1986-05-20
Publication date: 1986-12-30
Also published as: AU5797286A; AU579732B2; DE3661481D1; EP0206375B1

Abstract

Aqueous liquid detergent composition for simultaneous cleaning and softening of fabrics comprising a binary active suspending system, a long-chain fatty amine as softening agent and from 1 to 10% of a hydrotrope, the pH of the composition being below the isoelectric point of the amine component. A stable suspending composition is achieved delivering good cleaning and softening performance.

Description

The present invention relates to aqueous liquid detergent compositions of the suspending type, i.e. compositions in which particles of a different density can be stably suspended. In particular, the invention relates to aqueous liquid detergent compositions of the suspending type which exhibit good cleaning performance and simultaneously impart a softening quality to the fabrics being laundered.
Simultaneous cleaning and softening is desirable, as it provides the user with increased convenience in the laundering operation, rendering redundant the after-wash softening/rinse cycle and the separate dosing of special-purpose softening compositions.
A number of attempts have been made to formulate fabric-washing detergent compositions which exhibit the cleaning performance as expected by the modem user and simultaneously provide sufficient softening efficacy. In the field of solid detergent compositions, proposals have been made to incorporate cationic fabric softeners in anionic detergent-based compositions by inclusion of means which overcome the natural incompatibility of anionic and cationic detergent actives due to complexation of these compounds resulting in a consequent decrease in detergency and softening efficacy.
To our knowledge, no proposals have been made to formulate aqueous liquid compositions based on structured active systems including a combination of anionic and cationic detergent actives.
Surprisingly, it has now been found that long-chain fatty amines, which are suitable to impart through-the-wash softening, can be stably incorporated in aqueous suspending liquid detergent compositions at a pH equal to or below the isoelectric point of the amine without adverse effect on the suspending properties of the composition if a hydrotropic agent is included in an amount which will be defined hereunder more precisely.
Accordingly, the present invention provides an aqueous suspending liquid detergent composition for the cleaning and softening of fabrics which comprises:

(a) a nonionic detergent-active material and/or an anionic derivative of a polyalkoxylated nonionic detergent-active material; and
(b) an anionic detergent-active material other than component (a),

(c) an effective amount of a long-chain fatty amine; and
(d) 1-10% by weight of a hydrotropic agent;

In general the composition also comprises one or more electrolytes as part of the active system, thereby providing the structure necessary for the suspending properties of the composition.
The invention will now be discussed in more detail.

The nonionic detergent-active material

Suitable nonionic detergent-actives for use in the present invention may be found in the following classes: fatty acid alkylolamides, alkylene oxide condensates of alkylphenols or primary and secondary aliphatic alcohols, alkylamines, alkyl mercaptans and amine oxides.
The ethylene oxide condensates and mixtures of ethylene oxide condensates with fatty acid alkylolamides are preferred. Particularly suitable have been found ethylene oxides having a hydrophilic-lipophilic balance of between 11 and 15, such as C_"-C,₅ alcohols condensed with 6-8 ethylene oxides.
Also anionic derivatives of, in particular, polyalkoxylated nonionic detergent materials which have retained to a large extent a nonionic character, can be used instead of or in combination with nonionic detergent-actives. Suitable examples are the sulphated, phosphated or carboxylated polyalkoxylated nonionic detergent-actives, such as the alkyl and arkylaryl polyethoxy ether sulphates. Suitable alkyl polyethoxy ether sulphates have about 10 to about 18 carbon atoms in the alkyl chain and have an average of 1 to 12, preferably 1 to 6 ethylene oxide units.

The anionic detergent-active material

A wide range of anionic surfactants can be used in the compositions of the present invention.
Suitable anionic non-soap surfactants are water-soluble salts of alkyl benzene sulphonates, alkyl sulphates, paraffin sulphonates,alpha-olefin sulphonates, alpha-sulphocarboxylates and their esters, alkyl glyceryl ether sulphonates, fatty acid monoglyceride sulphates and sulphonates, 2- acyloxy-alkane-1-sulphonates, and beta-alkoxy alkane sulphonates. Soaps are also suitable anionic surfactants.
Especially preferred alkyl benzene sulphonates have about 9 to about 15 carbon atoms in a linear or branched alkyl chain, more especially about 11 to about 13 carbon atoms. Suitable alkyl sulphates have about 10 to about 22 carbon atoms in the alkyl chain, more especially from about 12 to about 18 carbon atoms.
Suitable paraffin sulphonates are essentially linear and contain from about 8 to about 24 carbon atoms, more especially from about 14 to about 18 carbon atoms. Suitable alpha-olefin sulphonates have about 10 to about 24 carbon atoms, more especially about 14 to about 16 carbon atoms; alpha-olefin sulphonates can be made by reaction with sulphur trioxide, followed by neutralization under conditions such that any sultones present are hydrolyzed to the corresponding hydroxy alkane sulphonates. Suitable alpha-sulphocarboxylates contain from about 6 to about 20 carbon atoms; included herein are not only the salts of alpha- sulphonated fatty acids, but also their esters made from alcohols containing about 1 to about 14 carbon atoms.
Suitable alkyl glyceryl ether sulphates are ethers of alcohols having about 10 to about 18 carbon atoms, more especially those derived from coconut oil and tallow. Suitable alkyl phenol polyethoxy ether sulphates have about 8 to about 12 carbon atoms in the alkyl chain and an average of about 1 to about 6 ethylene oxide units per molecule. Suitable 2-acyloxy-alkane-1-sulphonates contain from about 2 to about 9 carbon atoms in the acyl group and about 9 to about 23 carbon atoms in the alkane moiety. Suitable beta-alkyloxy alkane sulphonates contain about 1 to about 3 carbon atoms in the alkyl group and about 8 to about 20 carbon atoms in the alkane moiety.
The alkyl chains of the foregoing non-soap anionic surfactants can be derived from natural sources such as coconut oil or tallow, or can be made synthetically, as for example by using the Ziegler or Oxo processes. Water-solubility can be achieved by using alkali metal, ammonium, or alkanolammonium cations; sodium is preferred. Mixtures of anionic surfactants are contemplated by this invention; a satisfactory mixture contains alkyl benzene sulphonate having 11-13 carbon atoms in the alkyl group and alkyl sulphate having 12 to 18 carbon atoms in the alkyl group.
Suitable soaps contain about 8 to about 18 carbon atoms, more especially about 12 to about 18 carbon atoms. Soaps can be made by direct saponification of natural fats and oils such as coconut oil, tallow and palm oil, or by neutralization of free fatty acids obtained from either natural or synthetic sources. The soap cation can be alkali metal, ammonium or alkanolammonium; sodium is preferred.
The amount of the active detergent material may vary from 1 to 60%, preferably from 2-40% and especially preferably from 5-25%; when mixtures of e.g. anionics and nonionics are used, the relative weight ratio varies from 10:1 to 1:10, preferably from 6:1 to 1:6. When a soap is also incorporated, the amount thereof is from 1-40% by weight.
A particularly preferred active detergent mixture is that of a water-soluble anionic sulphonate or sulphate detergent and a nonionic detergent in a weight ratio of from about 6:1 to 1:1, with or without a soap in a ratio of up to 2:1 with respect to the nonionic detergent constituent.

The electrolytes

In order to establish the suspending properties of the compositions according to the present invention, the inclusion of one or more electrolytes, in particular of the salting-out type, is often essential.
It is well known that the extent to which a nonionic detergent-active or derivative thereof is salted out by a salting-out electrolyte, resulting in a certain lowering of the cloud point, is dependent upon the nature and the amount of salting-out electrolyte used. In general, the composition may contain from 1 to 60% by weight, and preferably from 3 to 50% by weight, and particularly preferably from 10 to 35% by weight of the salting-out electrolytes.
Typical examples of such salting-out electrolytes are water-soluble builder salts, such as the alkali metal ortho-and pyrophosphates, the alkali metal tripolyphosphates, such as sodium tripolyphosphate, the alkali metal silicates, alkali metal borates, alkali metal carbonates, alkali metal sulphates, alkali metal citrates; alkali metal salts of nitrilotriacetate; alkali metal salts of carbox- ymethyloxy succinate. instead of the alkali metal salts, the ammonium and ethanol-substituted ammonium salts can be used.
Depending upon type and level of salting-out electrolyte used, it may be advantageous to include also a certain level of a non-salting-out electrolyte. This can be determined by routine experimentation, using the general indications below as to level and type of auxiliary electrolytes.
Typical examples of suitable auxiliary electrolytes are alkali metal iodides, alkali metal (per)-chlorates, alkali metal rhodanides, and alkali metal nitrates, and alkali metal bromides and alkali metal chlorides. The corresponding ammonium and ethanol-substituted ammonium salts can also be used. The auxiliary electrolyte is generally used in the composition in an amount of 0.5 to 35% by weight, preferably 1 to 30% by weight, and particularly preferably 2 to 25% by weight.

The long-chain fatty amine

Long-chain fatty amines suitable for the purpose of the invention are substantially water-insoluble compounds that have the general formula:

wherein: R, is a C₁₀-C₂₆ alkyl or alkenyl group,
R2 is H or a C₁-C₂₆ alkyl or alkenyl group, and
R₃ is H or a C,-C, alkyl, alkenyl or alkylaryl group.
Preferably R₃ is methyl or ethyl. Suitable amines include:
- monotallowyl amine
- ditallowyl amine
- dilauryl methylamine
- dimyristyl methylamine
- dicetyl methylamine
- distearyl methylamine.

Preferred are monotallowyl amine, ditallowyl amine and ditallowyl methylamine. These are commercially available as Armeen HT, 2HT and M2HT from Akzo N.V..
Mixtures of any of these amines may be used.
The compositions should contain from 0.5% to 15% by weight of the amine, preferably from 1% to 10% by weight and most preferably from 2% to 5% by weight.

The hydrotropic agent

An essential aspect of the present invention is the inclusion of a hydrotropic agent. It has been found that such inclusion compensates the normally adverse effect on stability due to the incorporation of the at least partially charged amines.
Suitable hydrotropic agents for use in the present invention are those conventionally used for this purpose in the art. Suitable examples are the water-soluble organic solvents such as the lower alcohols, diols and triols, water-soluble organic compounds such as urea, the short alkyl chain aromatic sulphonic acid salts such as sodium toluene sulphonate and sodium xylene sulphonate.
The group of the short alkyl chain aromatic sulphonates is preferred.
The optimal amount of the hydrotropic agent depends on the type and concentration of the fatty amine, and can be simply determined by standard routines used in the art. In general, the hydrotropic agent is included in an amount of 1 to 10% by weight.

The pH

The pH of the composition is such that the fatty amine is at least partially protonated, and therefore is equal to or below the isoelectric point of the amine.
The isoelectric point of any given amine can be determined by measuring the electrophoretic mobility of an aqueous dispersion of the amine under standard conditions of concentration and temperature at a series of pHs, with plotting of the mobilities against pH to determine the pH of zero mobility.
The isoelectric points of a series of amines are given in the following table, in which T and Co represent the mixed alkyl radical derived from hydrogenated tallow acid and coconut oil acid, respectively.

T_zNH 7.4
T3N 8.2
T₂NCH₃ 8.8
Co2NCH₃ 9.1
TN(CH₃)₂ 10.0
THN₂ 10.9

Minor ingredients

The liquid detergent composition of the invention may further contain any of the adjuncts normally used in fabric-washing detergent compositions, e.g. sequestering agents such as ethylene diamine tetraacetate; alkali silicates for adjusting the pH; soil-suspending and anti-redeposition agents such as sodium carboxymethylcellulose, polyvinylpyrrolidone, etc.; fluorescent agents; perfumes, germicides and colourants.
Further, the addition of lather depressors such as silicones; and enzymes, particularly proteolytic and amylolytic enzymes; and peroxygen or chlorine bleaches, such as sodium perborate and potassium dichlorocyanurate, including bleach activators, such as N,N,N',N'-tetraacetylethylenediamine, may be necessary to formulate a complete heavy duty detergent compositions suitable for use in washing machine operations. These ingredients can be employed in the liquid detergent compositions of the invention without the danger of undue decomposition during storage if a proper protective coating is applied.
Preferably the composition of the invention has a viscosity of up to 1.2 Pas, and most preferably from 0.4 to 1.0 Pas as measured at 20°C and at a shear rate of 21 seconds-'.
The invention will now be further illustrated by way of examples, percentages in which are by weight of the total composition unless otherwise indicated.
Specifications and properties of ingredients:

Armeen HT = primary hardened tallow amine R-NH₂
melting range : 47-55°C
isoelectric pH : 10.9 M = 256
R : C₁₆ ⁼ 31% C ₁₈= 59%
supplier : AKZO Chemie
Synperonic K87 = C₁₃-C₁₅ fatty alcohol condensed with 7 moles of alkylene oxide (92% ethylene oxide, 8% propylene oxide)
STP = Na₅P3O₁₀: Thermphos NW; ex Knapsack
Glycerol = C₃H₈O₃ (8₆.5%), water (13.5%)

Example

Claims

1. Aqueous suspending liquid detergent composition for the cleaning and softening of fabrics, comprising:

(a) a nonionic detergent-active material and/or an anionic derivative of a polyalkoxylated nonionic detergent-active material; and

(b) an anionic detergent-active material other than component (a),

characterized in that the composition further comprises:

(c) an effective amount of a long-chain fatty amine; and

(d) 1-10% by weight of a hydrotropic agent;

the pH of the composition being equal to or below the isoelectric point of said amine.

2. Composition according to claim 1, which further comprises as component (e) from 1-60% by weight of electrolytes of the salting-out type.

3. Composition according to claim 2, which comprises from 10-35% by weight of component - (e).

4. Composition according to claim 2 or 3, which further comprises as component (f) from 0.5-35% by weight of electrolytes of the non-satting-out type.

5. Composition according to any one of the preceding claims, wherein component (c) has the general formula:

wherein R, is a C₁₀-C₂₅ alkenyl group,

R₂ is H or a C₁-C₂₆ alkyl or alkenyl group, and

R₃ is H or a C,-C, alkyl, alkenyl or alkylaryl group.

6. Composition according to claim 5, wherein R₃ is methyl or ethyl.

7. Composition according to claim 5, wherein the amine is a monotallowyl amine, a ditallowyl amine or a ditallowyl methyl amine.

8. Composition according to any one of the preceding claims, which comprises from 0.5-15% by weight of component (c).

9. Composition according to any one of the preceding claims, wherein component (d) is a short alkyl chain aromatic sulphonate.

10. Composition according to any one of the preceding claims, which has a pH at which component (c) is at least partially protonated.