EP0126500A1

EP0126500A1 - Low-sudsing liquid detergent compositions

Info

Publication number: EP0126500A1
Application number: EP84200508A
Authority: EP
Inventors: Guido Clemens Van Den Brom
Original assignee: Unilever PLC; Unilever NV
Current assignee: Unilever PLC; Unilever NV
Priority date: 1983-04-20
Filing date: 1984-04-11
Publication date: 1984-11-28
Also published as: FI841476A0; ES531790A0; GB8310648D0; FI841476A; PT78451A; PT78451B; GR81471B; ES8602925A1

Abstract

The invention pertains to low-sudsing liquid detergent composition comprising a micellar structured liquid and a suds-suppressant, characterized in that the suds-suppressant comprises an intimate mixture of an oily substance and a nitrogen compound of the general formula:

where R¹ and R³ represent aliphatic hydrocarbon residues containing 14-22 carbon atoms, R² and R⁴ represent hydrogen atoms or aliphatic hydrocarbon residues containing 1-22 carbon atoms, and R represents an aliphatic residue containing 1-9 carbon atoms. The invention provides low-sudsing liquid compositions which do not suffer from deactivation of the suds-suppressant.

Description

This invention relates to low-sudsing liquid detergent compositions.
Low-sudsing detergent compositions are increasing in popularity as the number of front-loading, drum-type washing machines and fully automatic industrial washing machines increases. Although much of the market is concentrated in the powder sector, liquid compositions are now being introduced in a number of European countries.
The conventional suds-suppressant for liquid compositions is a hydrocarbon oil or a silicone oil, since these materials are themselves liquid and in theory at least are capable of incorporation into liquid compositions without undue complication. In practice there are a number of difficulties with incorporating suds-suppressants into liquid compositions. For example it has been found that in general silicone oils are deactivated by the alkaline medium of a liquid detergent composition, and need to be protected.
We have now discovered that suds-suppressant combinations of various complex nitrogen compounds with oily substances can be incorporated into certain liquid detergent compositions relatively simply and without problems of deactivation.
Accordingly, the present invention provides a low-sudsing liquid detergent composition comprising a micellar structured liquid and a suds-suppressant, characterised in that the suds-suppressant comprises an intimate mixture of an oily substance and a nitrogen compound of the general formula:

where R¹ and R³ represent aliphatic hydrocarbon residues containing 14-22 carbon atoms, _R ² and _R ⁴ represent hydrogen atoms or aliphatic hydrocarbon residues containing 1-22 carbon atoms, and R represents an aliphatic residue containing 1-9 carbon atoms.
It will now be apparent that this invention relates to a micellar structured liquid.
There are two basic ways of making structured or false body liquids. One way is to rely on the micellar interaction set up between an anionic surfactant, a nonionic surfactant and an electrolyte. If a combination of this sort is incorporated into a liquid it is possible to produce a structure which is capable of suspending as much as 50% of quite dense particles such as sodium tripolyphosphate.
The second way of making a structured liquid is to use an auxiliary thickener such as a clay or a polymer. Again quite larger amounts of particulate material can be suspended in such liquids, but in our experience their viscosity is more sensitive to changes in formulation.
We believe we are one of the very few organisations who have investigated the application of micellar structured liquids to the field of fabric washing in automatic washing machines. Hitherto, the structured liquids produced or patented by our competitors have generally been part of hard surface cleaning compositions such as scouring cleansers. Such compositions are very different from fabric washing compositions in that the detergency required of them is much lower. Furthermore, the amount of foam developed is not especially important. In fabric washing compositions, on the other hand, the amount of foam developed is critical, since if the compositions develop large amounts of foam, then they will not be suitable for use in automatic washing machines.
In a preferred aspect, the invention provides a stable homogeneous aqueous structured micellar liquid detergent composition, containing suspended sodium tripolyphosphate and 6 to 20% by weight of an active detergent mixture comprising:

(a) a water-soluble anionic sulphonate or sulphate detergent;
(b) an alkali metal soap of a fatty acid having 12 to 22 carbon atoms;
(c) a nonionic detergent;

Water-soluble anionic sulphonate detergents suitable for use in the compositions of the invention are, for example, the alkali metal salts of ^C ₁₀-^C ₁₆ alkylbenzene sulphonates, C₁₀-C₂₀ alkane sulphonates, and C₁₀-C₂₀ olefin sulphonates, the alkali metal salts of alkylbenzene sulphonates being preferred, especially those derived from alkylbenzenes having a C₁₀-C₁₄ alkyl chain and average molecular weight of approximately 225-245.
Water-soluble anionic sulphate detergent are for example primary and secondary alkyl sulphates and alkylether sulphates having an alkyl chain length of about 8 to 20 carbon atoms, preferably 12 to 18 carbon atoms e.g. lauryl sulphate.
Typical examples of fatty acids having 12 to 22 carbon atoms are oleic acid, ricinoleic acid, and fatty acids derived from castor oil, rapeseed oil, groundnut oil, coconut oil, palmkernel oil or mixtures thereof. The sodium or potassium soaps of these acids can be used, the sodium soaps being preferred.
Suitable nonionic detergents for use in the present invention are fatty acid alkylolamides; alkylene oxide condensates of alkyl phenols or aliphatic alcohols, alkylamines, fatty acid alkylolamides and amine oxides. Ethylene oxide condensates of alkyl phenols or aliphatic alcohols are preferred.
Particularly suitable ethylene oxide condensates, such as C₁₂-C₁₅ alcohols condensed with 6-8 moles of ethylene oxide per mole of alcohol have hydrophilicli- pophilic balance (HLB) values of between 11 and 15. Preferably the compositions of the invention have a viscosity of from 0.3 to 1.5 Pa.s measured at 20°C and at a shear rate of 21 seconds-1; a sodium tripolyphosphate content of 8 to 30% by weight and an active detergent mixture content of 8 to 20% by weight.
While it is normally necessary to have the surfactant mixture in the stated ratios in the aqueous compositions in order to achieve a stable product within the desired viscosity range, it has been found that it is also important to mix the ingredients, properly agitated, in the proper sequence in order to produce a product of uniform quality from batch to batch. If the mixing sequence and proper agitation disclosed below are not followed, varying rheological properties and reduced suspending capability can occur. If the mixing order and proper agitation as described below are followed, then successive batches especially when mixed in the same vessel will produce products of uniform viscosity and stability.

Example 1

The pH of this product was adjusted to a value of 13.
When used in an automatic washing machine of the (semi)-industrial type the suds generated by the liquid composition was at a controlled level, even after prolonged storage of the liquid.
The ingredients are preferably mixed in the following manner.
The required quantity of water is charged into a suitable mixing vessel provided with a stirrer. Sodium tripolyphosphate and sodium metasilicate are then mixed into the water and sodium hydroxide is added with heating to about 60°C. The oleic acid is then mixed into the mass and stirring is continued at 60°C to saponify the oleic acid. Methylene bis-stearamide and petroleum jelly are then pre-mixed with nonionic surfactant at 60°C and this mix is then added to the main mix with continuous stirring. Subsequently the alkyl benzene sulphonic acid is mixed into the mass. Finally the mixture is cooled under constant agitation and water is added, if necessary, to compensate for evaporation loss during the first stages of operation. Thereafter, perfume may be added when the product is at substantially ambient temperature.
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-diaminetetraacetate and sodium gluconate; alkali silicates for adjusting the pH; soil suspending and anti-redeposition agents such as sodium carboxymethylcellulose, polyvinyl-pyrrolidone etc; fluorescent agents; perfumes, germicides and colourants.
Further the addition of suds-suppressants other than those defined; enzymes, particularly proteolytic and amylolytic enzymes, particularly proteolytic and amyolytic enzymes; reducing peroxygen or chlorine bleaches, such as sodium sulphite, sodium perborate and potassium dichlorocyanurate, including bleach activators, such as N,N,N',N'- tetraacetylethylene- diamine, may be necessary or desirable to formulate a complete heavy duty detergent composition suitable for use in washing machine operations. These ingredients can be employed in the liquid detergent compositions of the invention without danger of undue decomposition during storage if a proper protective coating is applied.

Claims

1. A low-sudsing liquid detergent composition comprising a micellar structured liquid and a suds-suppressant, characterized in that the suds-suppressant comprises an intimate mixture of an oily substance and a nitrogen compound of the general formula:

where R¹ and R³ represent aliphatic hydrocarbon residues containing 14-22 carbon atoms, _R ² and _R ⁴ represent hydrogen atoms or aliphatic hydrocarbon residues containing 1-22 carbon atoms, and R represents an aliphatic residue containing 1-9 carbon atoms.

2. A composition according to claim 1, characterized in that it comprises:

(I) 6 to 20% by weight of an active detergent mixture comprising:

(a) a water-soluble anionic sulphonate or sulphate detergent;

(b) an alkalimetal soap of a fatty acid having 12 to 22 carbon atoms; and

(c) a nonionic detergent;

(II) suspended sodium tripolyphophate; and

(III) an intimate mixture of an alkylene distearamide and wax.

3. A composition according to claim 1 or 2 characterized in that it comprises 8 to 20% by weight of an active detergent mixture, and 8 to 30% by weight of a sodium tripolyphosphate, having a viscosity within the range of from 0.3 to 1.5 Pa.s measured at 20°C and at a shear rate of 21 sec.^-1.

4. A composition according to any of the preceding claims characterized in that it comprises an intimate mixture of methylene distearamide and petroleum jelly.

5. A process for the preparation of a composition according to any of the preceding claims characterized in that the nitrogen compound is premixed with the oily substance to intimate mixture before addition to the remaining ingredients of the composition.