NO781577L - LIQUID DETERGENT MIXTURE, AND PROCEDURE FOR THE PREPARATION OF SUCH - Google Patents

Description

Liquid detergent mite mixture, as well as method for producing such.

The invention relates to an aqueous, liquid detergent mixture comprising soap and a non-soap detergent.

Aqueous liquid detergents are well known in the art. Typically, such products contain one or more synthetic organic detergents, solvents and, in the case of builder aqueous liquid detergent mixtures, inorganic and/or organic builder salts. Often such products also contain hydrotropes, which enable the incorporation of sufficient amounts of detergent material and building salts to achieve the desired physical properties, as well as satisfactory washing performance.

When putting together such aqueous liquid detergent mixtures, physical properties such as storage stability, clarity, viscosity, pourability etc. play an important role,

as well as washing power and foaming properties in the volume in which the product is to be used. Thus, for example, even if a particular product can provide satisfactory washing power and foaming in a certain dosage, you often see a significant decrease in performance if it is used smaller dosages. This is especially true in such situations where the dosage is insufficient to render the water hardness ions inactive, i.e. in so-called "substantial" situations. Out

from an ecological point of view, reducing the amount of phosphate-building salts could be desirable, but such a reduction causes a reduction in washing ability, especially in a well-built situation.

It has already been proposed in the state of the art to put together so-called unbuilt liquid detergent mixtures, which are products that are free of building salts. Thus, British Patent No. 1,370,402 discloses unstructured liquid detergent compositions comprising a nonionic surfactant, an anionic

surfactant which is an alkanolamine salt of C-C. _-

y ib alkylbenzenesulfonic acid or of Cg-C^ fatty acids, further a free Cg-C24 fatty acid and a solubilizing agent.

British Patent No. 1 365 464 describes unstructured liquid detergents comprising a nonionic surfactant, a mixture of an alkanolamine salt of C 1 -C 4 -alkylbenzenesulfonic acid and of C 8 -C 4 -fatty acids, and free ethanoiamine.

However, these attempts are not entirely satisfactory, as the achievement of one or more desired characteristics often involves a significant reduction of other desirable characteristics. Therefore, the above-mentioned recipes may suffer from too low a foaming capacity or from poor washing ability at higher dosages.

Furthermore, these recipes are aimed at mixtures where the soap component is an alkanolamine salt, which is more soluble than the more readily available sodium soaps. The present invention is, however, directed at soap-based liquid detergent mixtures in which the soap component is or comprises a sodium soap.

Liquid detergent compositions which may include a sodium soap have been proposed in the prior art. For example, US Patent No. 2,875,153 discloses a liquid detergent composition in gel form containing a water-soluble soap and a non-ionic detergent. The water-soluble soap may be a sodium soap. However, this product is a gel, which makes it unsuitable as a liquid detergent mixture due to its viscosity and its pourability characteristics.

US Patent No. 2,543,744 discloses a low sudsing detergent composition comprising an alkali metal soap and a nonionic surfactant. These mixtures, when in the form of an aqueous liquid with a sodium soap, contain up to 7.5%

of the latter.

Numerous other proposals have been made with respect to liquid detergents containing a soap component. Thus, US patent no. 3,723,328 refers to products that can contain up to

to 16.2% of a sodium soap, and US patent pending. 3,707,503 discloses constructed products which may contain up to 4.5% of a sodium soap.

British Patent No. 1,415,719 discloses liquid compositions containing a liquid non-ionic substance and fatty acids, which may be partially neutralized to form sodium soaps, and British Patent No. 1,081,556 discloses liquid detergent compositions in which part of the soap component may be a sodium soap.

Dutch patent application 7413265 and German patent application no. 2 411 528 relate to liquid products comprising a mixture of sodium soaps of Cg-C14 saturated and C-^-C^-unsaturated fatty acids, together with other synthetic detergents and possibly building salts.

Dutch Patent Application 7406004 discloses a liquid product containing up to 8% of an alkali metal soap as well as up to 60% of a mixture of nonionic surfactants, and US Patent No. 2,560,839 discloses a liquid product containing up to 10 % of an alkali metal soap, up to 30% of a non-ionic surfactant and up to 30% of a pyro-phosphate builder salt. Although all these attempts provide products suitable for certain laundry purposes, they are less suitable for other cleaning operations, especially at different dosages and/or in substantiated situations.

It has now been shown that satisfactory liquid detergent compositions can be achieved which are isotropic, contain ecologically acceptable components, which are particularly suitable in the under-built range of dosages, but which also show, at higher dosages, the superior detergency characteristics of constructed products compared to conventional unbuilt liquid products.

The discovery of such useful products has been made possible by the use of high levels of fatty acid sodium soaps combined with the incorporation of suitable levels of synthetic detergent and certain buffering agents which enhance the detergency performance of these liquid soap products.

The invention therefore relates to an aqueous, liquid detergent mixture which, as essential ingredients, comprises: a) at least 10% by weight, calculated on the mixture, of a sodium soap of a straight-chain or branched C8~C24-^acetic acid'b) at least 1% by weight, calculated on the mixture , of an organic synthetic detergent, the weight ratio between the sodium soap and the organic synthetic detergent being from 10:1 to 1:1; c) at least 0.1% by weight, calculated on the mixture of a buffering agent as defined below.

Such aqueous, liquid detergent mixtures are effective at lower dosages in built-up situations and are superior to other conventional unbuilt liquid products at higher dosages, where they can even behave as built-up liquids. The products according to the invention have superior performance at lower dosages compared to conventional built liquids at lower dosages.

The essential ingredients in the product according to the invention shall be described in detail below,

a. The soap component.

The soap component is, or comprises, a sodium soap of straight-chain or branched fatty acids with 8-24 carbon atoms in the alkyl residue. These fatty acids include saturated and unsaturated natural fatty acids, as well as synthetic fatty acids. The latter may show a certain degree of branching in the alkyl residue, e.g. up to 20% methyl groups in the a-position in the alkyl residue. Typical examples of suitable fatty acids include caprylic->capric, lauric, myristic, palmitic, stearic, oleic, linoleic, behenic acids as well as mixtures of such fatty acids. Fatty acids obtained from natural fats and oils are also suitable, e.g. coconut oil fatty acids, palm and palm kernel fatty acids, fatty acids derived from soybean oil, safflower oil, tall oil, tallow, fish oil, lard, peanut oil, castor oil and the like. Examples of synthetic fatty acids include those obtained by oxidation of petroleum or by hydrogenation of carbon monoxide according to the Fischer-Tropsch process.

The preferred sodium soaps are sodium oleate, the sodium salt of coconut fatty acids and mixtures thereof. In the latter case, the weight ratio between the two components varies from 9:1 to 1:9, preferably 4:1 to 1:4.

The minimum amount of sodium soap that must be present in the product is approx. 10% by weight. The invention enables the incorporation of high levels of sodium soap, i.e. that up to 60% by weight of the sodium soap can be incorporated. Generally, for the most practical purposes, the amount of the sodium soap will be from 15-50, especially from 20-35, wt% of the mixture.

Other soaps with a different cation, e.g. potassium soaps,

and alkanolamine soaps can also be incorporated, when only the amount of sodium soap lies within the ranges indicated above.

The sodium soaps can be added to the products as such, or they can be formed in situ by neutralizing the corresponding fatty acids in the product by adding a suitable sodium salt-forming alkaline material, e.g. caustic cloth and caustic soda. The same applies to the possibly simultaneously used soaps with a different cation.

b. The organic synthetic detergent.

This ingredient can be selected from the group consisting of anionic, nonionic, cationic, zwitterionic and amphoteric organic synthetic detergents. The anionic synthetic detergents (the designation excludes salts of natural or synthetic fatty acids) are in principle compounds with a hydrophobic radical and a solubilizing salt-forming anion, e.g. sulfate, sulfonate and phosphate anion et.

Typical examples are Cg-C.j_g-straight chained or branched alkylaryl sulfonates, Cg-C22-Primary or secondary alkyl sulfates, Cg-C22~Pr;'-mers or secondary alkanesulfonates, Cg-C^-α-olefin sulfonates, Cg -C22~Pr:i-primary or secondary alkyl ether sulphates, containing 1-15 mol of ethylene oxide, propylene oxide, butylene oxide or mixtures thereof, sulphonated fatty acids or fatty acid esters, Cg-C2^-acyltaurides,<C>g<-> C₁-acylisethionates, C₂-C₂-₂-alkyl or alkylaryl phosphates or ether phosphates with 1-10 mol of ethylene oxide, propylene oxide or mixtures thereof. Alkyl polyglycol ether carboxylic acid salts are also covered by the term anionic synthetic detergents. Further examples of anionic synthetic detergents are described in standard textbooks, e.g. Schwartz, Perry and Berch: "Surface-active Agents and Detergents", Volume I (1949) and Volume-II (1958). These anionic materials are used in the form of their sodium, potassium, ammonium or alkanolamine salt.

The non-ionic synthetic detergents generally comprise compounds that have a hydrophobic radical and a water-solubilizing group that does not ionize. Normally, this water solubilization is effected by ethoxylation and/or propoxylation of a hydrophobic molecule containing a removable proton.

Typical examples are the ethoxylation and/or propoxylation products of linear or branched, primary or secondary, natural or synthetic alcohols, which have 8-24 carbon atoms in their alkyl chain, of mono- or dialkylphenols with 8-18 carbon atoms in their alkyl chain, of cq~ C22~^acetic acids (as defined for the sodium soaps above), of polyethylene or polypropylene glycols, of C0-C„_ fatty acid amides, -fatty acid amides or -fatty acid alkylolamides, etc. Further examples are given in the standard textbook referred to above . The non-ionic detergents are also to be understood the tertiary amine oxides which have one alkyl chain with 8-18 carbon atoms and 2 alkyl chains with 1-5 carbon atoms, which may be substituted or ethoxylated, as well as sucrose esters.

Typical examples of cationic synthetic detergents

are quaternary ammonium compounds, e.g. the (di)-higher alkyl-di-(lower) alkylammonium chlorides. Further examples are again given in the standard textbook referred to above.

Zwitterionic synthetic detergents are e.g. the sulfo-betaines, e.g. alkyldimethylammoniumpropanesulfonate, and amphoteric synthetic detergents are e.g. the mono- or dialkyl-α-aminocarboxylic acids.

Examples of zwitterionic or amphoteric synthetic detergents are also disclosed in the standard textbook referenced above. Their salt-forming cation can be a sodium, potassium, ammonium or an alkanolamine cation.

Naturally, mixtures of these synthetic detergents, either of the same class or of a different class, can be used, e.g. a mixture of two different anionic or nonionic detergents, or a mixture of an anionic and a nonionic detergent. In general, at least 1% of the synthetic organic detergent should be present in the liquid product. The maximum level can be as high as 50% by weight, and for most practical purposes the amount ranges from 5 to 40, preferably from 9 to 30% by weight.

The preferred synthetic detergents are the calcium-insensitive synthetic detergents, which have lime soap dispersing properties, e.g. nonionic and alkyl ether sulfates.

Generally, the weight ratio of the sodium soap to the synthetic organic detergent is from 10:1 to 1:1, and preferably from 3:1 to 1:1.

c. The buffering agent.

The buffering agent used according to the invention can be an organic and/or inorganic source of alkalinity, which exerts a buffering capacity for providing and maintaining the washing bath, produced from the liquid detergent mixture, at the appropriate pH value, which normally lies in the range 7-11, preferably 8-10. The buffering agent can be a substance that is also used to neutralize special acid substances in the product, and in this case an excess of the buffering agent should be used so that the minimum level of 0.1% by weight of free buffering agent will be present in the liquid product;

The buffering agent can be an inorganic alkaline material, e.g. NaOH, alkali silicates, carbonates and metacarbonates, but the buffering agent is preferably an organic base, e.g. morpholine, piperazine, as well as the alkanolamines, e.g. the mono-, di- and triethanolamines, the mono-, di- and trippropanolamines and the mono-, di- and triisopropanolamines. Of these, the alkanolamines are preferred. Tri-ethanolamine is preferred for a low pH buffer, and monoisopropanolamine is preferred for a high pH buffer.

At least 0.1% by weight of the buffering agent should be present,

and the maximum level is approx. 20% by weight. Normally 1-15, and especially 2-10, wt% will be required for optimum properties.

The products according to the invention can further include a number of non-essential, but often desirable, possible ingredients.

Thus, the products may comprise a solvent or a hydrotropic system. Such systems help to improve the physical properties of the product, e.g. clarity, viscosity and phase stability. Solvents include the lower aliphatic alcohols, glycols and mono- or dialkyl glycol ethers, hydrocarbons, tetrahydrofurfuryl alcohol, etc. The hydrotropes include sodium, potassium, ammonium or alkylolamine salts of xylene, toluene and cumenesulfonic acid, urea, monoalkane phosphonates and the like. Mixtures of solvents and hydrotropes can also be used.

In general, the amount of solvent or hydrotrope varies from 0 to 10% by weight, calculated on the mixture.

The product may also contain foam-enhancing agents, e.g. the fatty acid alkylolamides, defoamers, e.g. silicones, preservatives, antioxidants, chelating agents, perfumes, fluorescent agents, dyes, germicides, bactericides, enzymes and enzyme stabilizers, dirt-carrying agents, anti-fog deposition agents, opacifying agents, electrolyte salts, e.g. alkali metal chlorides, sulphates, acetates and the like.

All these additional ingredients are normally used in small amounts, e.g. in the order of 0.1-2% by weight.

As indicated earlier, the liquid detergent compositions according to the invention can be assembled into an unbuilt product, which is preferred, but it is also possible to include building salts. Any of the conventional organic and/or inorganic building salts can be used, e.g. the building salts of the phosphate type, e.g. sodium or potassium ortho-, -pyro- or -tripolyphosphate, further salts of carboxymethyloxysuccinate, calcium carbonate, citrates, nitrile triacetic acid, sodium aluminosilicates of the molecular sieve type, as well as other well-known building salts. If building salts are incorporated, their amount may vary from 1 to 35%, preferably 5 to 30%, by weight of the mixture. In this regard, it has also been found that even small amounts of a builder in these products give improved washability effects on cotton at 60°C.

The products according to the invention are particularly well suited for washing clothes, especially of mixed fabrics of polyester and cotton, and they have been shown to possess unusually good rinsing properties. They are isotropic liquids, in that they have excellent physical stability under freeze/thaw conditions.

The products according to the invention can be prepared in any suitable way, but it has been found to be advantageous to add the ingredients in such an order that the sodium soaps are formed last, by in situ neutralization. Therefore, a preferred method consists of the following steps*.

Add in sequence:

1. the fatty acids and melt them; 2. the fluorescent agent, preferably pre-dispersed in a non-ionic surfactant; 3. preservatives; 4. the remainder of nonionic surfactant; 5. puffs; 6. hydrotropic; 7. neutralizing agent in the form of an aqueous solution;

8. water and perfume, if desired.

In what follows, the invention will be illustrated by means of examples.

Example I

The following clear isotropic liquid product was prepared:

This liquid was an isotropic liquid with a freezing point of 3-4°C.

Example II

An isotropic liquid with the following composition was produced:

This liquid was clear and remained stable for extended periods of storage at temperatures between -5 and +50°C.

Example III

The following isotropic fluid was prepared:

Example IV

The following build fluid was produced:

Example V

The following unstructured liquid detergents were prepared:

Example VII

The liquid from Example I was compared in a Tergotometer in a washing test with a product according to British Patent No. 1,365,464, containing 33% non-ionic, 12% anionic and 10.5% triethanolamine as a base system. The washings were carried out in water of 6°FH at approx. 25°C, using 1 kg of 50% soiled fillings for 8 minutes, followed by three rinses. Washability was measured using ERTC 41 A and AS 12 test pieces, and fluorescence and redeposition were measured using non-fluorescent cotton pieces. The products were used at concentrations of 0.7, 1.0, 1.5 and 2.0 g/l.

The washability results (reflectivity) were as follows:

The product of Example 1 was superior, especially at higher dosages.

Claims (17)

1. Aqueous, liquid detergent mixture comprising: (a) at least 10% by weight, calculated on the whole mixture, of one or more sodium soaps of C 8 -C 3 -chained, or branched, saturated or unsaturated fatty acids; (b) at least 1% by weight, calculated on the entire mixture, of one or more organic synthetic detergents, the weight ratio between sodium soap and organic synthetic detergent being from 10:1 to 1:1; and (c) at least 0.1% by weight, calculated on the entire mixture, of a buffering agent which buffers the washing liquid to a pH value of 7-11. 2. Detergent mixture as stated in claim 1, characterized in that the sodium soap is sodium oleate, sodium soap of coconut fatty acids or a mixture thereof. 3. Mixture as stated in claim 1 or 2, characterized in that it comprises 10-60% by weight, calculated on the whole mixture, of the sodium soap. 4. Mixture as stated in claim 3, characterized in that it comprises 15-50% by weight, calculated on the whole mixture, of the sodium soap. 5. Mixture as stated in claim 1, characterized in that it comprises 20-35% by weight, calculated on the whole mixture, of the sodium soap. 6. Mixture as stated in claims 1 to 5, characterized in that the organic synthetic detergent is a non-ionic synthetic detergent or an alkyl ether sulfate. 7. Mixture as stated in claims 1 to 6, characterized in that it comprises 1-50% by weight, calculated on the whole mixture, of the organic synthetic detergent. 8. Mixture as specified in claim 7, characterized in that it comprises 5-40% by weight, calculated on the entire mixture, of the organic synthetic detergent. 9. Mixture as stated in claim 8, characterized in that it comprises 9-30% by weight, calculated on the entire mixture, of the organic synthetic detergent. 10. Mixture as stated in claims 1 to 9, characterized in that the buffering agent is an alkanolamine. 11. Mixture as stated in claim 10, characterized in that the buffering agent is triethanolamine or monoiso-propanolamine. 12. Mixture as stated in claims 1 to 11, characterized in that it comprises 0.1-20% by weight, calculated on the entire mixture, of the buffering agent. 13. Mixture as stated in claim 12, characterized in that it comprises 1-15% by weight, calculated on the entire mixture, of the buffering agent. 14. Mixture as stated in claim 13, characterized in that it comprises 2-10% by weight, calculated on the whole mixture, of the buffering agent. 15. Mixture as stated in claims 1 to 14, characterized in that the weight ratio between the sodium soap and the organic synthetic detergent is from 3:1 to 1:1. 16. Mixture as stated in claims 1 to 15, characterized in that it comprises 1-35% by weight, calculated on the mixture, of a builder's salt. 17. Method for producing a detergent mixture as stated in claims 1 to 16, where the different ingredients are mixed together, characterized by the step that the soap is finally formed, by in situ neutralization of the fatty acid.