EP0662510A1 - Hydrotropic agents and compositions containing them - Google Patents

Abstract

Hydrotrope compsns. comprise a major amt. of 6-10C alkyl sulphonate(s) (I) and a minor amt. of 4-12C alkyl and/or alkylene sulphonate(s) (II) contg. one or more sulphonate gps. and opt. one or more other functional gps. Also claimed is a detergent compsn. comprising a surfactant and a hydrotrope as above.

Description

The present invention belongs to the field of surfactant detergents and relates more particularly to hydrotropic agents intended to allow the formulation in high concentration of detergents.

According to the invention, the term “tensioactivity” means the property of a product in solution of lowering the interfacial tension associated with an increase in the concentration of the product at the interface.

By hydrotropy is meant the property of a product to increase the solubility of a substance in water, without this product being a solvent in itself. This property will be particularly exploited in the invention, to dissolve in water high concentrations of surfactant detergents.

A hydrotropic agent can also have surfactant properties.

Today, preparations based on surfactants, in particular surface-active detergents, are advantageously formulated in concentrated quantities and this for all of their industrial and consumer-oriented applications, such as fiber detergents, hard surface detergents, various cleaning products, cosmetics, metalworking products ...

Indeed, although being more complex to prepare for the manufacturer, the concentrated formulations of surfactants are advantageous for the user, because they are more economical, less bulky, less heavy to transport. This concerns both liquid preparations, whether they are monophasic or multiphase, as well as solid preparations generally prepared from highly concentrated multiphase liquid preparations.

To obtain such liquid preparations, the formulator has at its disposal a certain number adjuvants among which are found the stabilizing dispersing agents, and the solubilizing or hydrotropic agents.

A good hydrotropic agent must not only dissolve the detergent in water when it is present in high concentrations, but it must also stabilize the formulation obtained, and this at fairly low temperatures, when the use makes it necessary.

In addition to their hydrotropic nature, the solubilizing agents must meet regulatory standards regarding their toxicity and biodegradability, as well as the wishes of users, in particular concerning the impact of these agents on the environment. Thus, these agents must be little or not harmful to humans and the environment, not bioaccumulative, biodegradable, non-volatile and must not release resistant by-products.

Among the hydrotropic agents commonly used, there are solvents of the alcohol type, low molecular weight arylsulfonates, such as benzene sulfonates, toluene sulfonates, xylenesulfonates, cumenesulfonates, as well as short carbon chain alcohols , preferably 8 carbon atoms.

All of these hydrotropic agents have drawbacks.

Alcoholic solvents are mostly volatile and fall into the category of VOCs (Volatile Organic Compound) which, due to their volatility, can contribute to the reduction of the ozone content and to the greenhouse effect. They are also easily flammable.

Aryl sulfonates, due to the presence of aromatic nuclei in their structure, are believed to lead to relatively persistent by-products that are harmful to the aquatic environment. Finally the alcohol sulfates are easily hydrolyzable and therefore of more limited use.

According to document FR-A-2 148 120, the use of monosulfonated alkyl sulfonates, having either 7 or 8 carbon atoms, as hydrotropic agent, which can be incorporated into detergent compositions, is described. . The hydrotropic nature of such agents is no longer always sufficient for the detergent preparations currently marketed, which are very concentrated in surfactant detergent agent.

In addition, such agents are preferably presented in liquid form, which requires a significant dilution for their implementation, which is disadvantageous economically.

The object of the present invention is a hydrotropic agent which on the one hand has good water solubility and excellent hydrotropy, but which on the other hand is non-volatile and completely biodegradable.

This hydrotropic agent which exerts in particular its effect on detergent surfactant compounds, whether they are anionic, nonionic or amphoteric, has in addition surfactant properties which complement those of the solubilized surfactant compound, which from an economic point of view n is not negligible.

According to the invention, the hydrotropic agent comprises, on the one hand a majority fraction by weight of at least one mono-sulfonated alkyl sulfonate, having from 6 to 10 carbon atoms, and a minority fraction of at least one alkyl -sulfonate, different from that of the majority fraction, and / or at least one alkylene sulfonate, having from 4 to 12 carbon atoms, mono- or poly-sulfonate, and optionally substituted by at least one other different functional group of the sulfonate group.

According to a particular hydrotropic agent of the invention, the minority fraction comprises several alkyl sulfonates and / or alkylene sulfonates.

The respective weight concentrations of the two fractions, minority and majority, relative to the total weight of the agent depend on the number of constituents of the hydrotropic agent. However, the weight concentration of the majority fraction is always higher than that of the constituent of the minority fraction, having the highest concentration.

Preferably according to the invention, at least one alkyl sulfonate of the majority fraction is chosen from alkyl-1-sulfonates and more advantageously at least one alkyl sulfonate of said fraction is octyl-1-sulfonate.

When the alkyl-sulfonate and / or the mono- or poly-sulfonate alkylene sulfonate of the minority fraction is substituted by at least one other functional group different from the sulfonate group, said group is chosen in particular from hydroxyl and sulfinate groups.

The hydrotropic agents meeting the definition of the present invention have a solubilizing power often greater than that of the arylsulfonates commonly used today, and therefore allow access to new presentations of even more concentrated detergent compositions.

Compared to the hydrotropic agents described according to FR-A-2 148 120 mentioned previously in the description, the hydrotropic agents of the invention, obtained by the specific mixture described above, have, under the same conditions, greater solubility, an easier, or more concentrated, commercial presentation for an identical cold resistance, therefore more economical, and confer better stability of the resulting preparations, at low temperature.

Another subject of the invention is a detergent composition comprising a surfactant compound and an agent hydrotropic of said surfactant, in accordance with the invention.

In addition, the hydrotropic agents of the invention give the compositions containing them a better resistance to crystallization, under the effect of the lowering of the temperature, and have a low foaming power, which allows their easy handling.

In addition, these agents have good resistance to hydrolysis, in a wide pH range, and good resistance to oxidizing products such as hypochlorites for example.

The characteristics and advantages of the present invention are now illustrated by the following Examples 1 to 4, in which Examples 1 to 3 illustrate methods for obtaining hydrotropic agents of the invention and Example 4 illustrates compositions of the invention.

EXAMPLE 1

In a first stirred heating reactor, 201.6 g of C₈ α-olefin, 151.2 g of isopropranol, 97.2 g of water and 10.44 g of tert-butyl-perbenzoate are placed.

Heated to 76-78 ° C with stirring and maintained at reflux for 30 minutes.

In a second reactor, 291 g of water are placed and 145 g of sodium metabisulfite and then 39.7 g of 30% sodium hydroxide solution are introduced with stirring. After dissolution, a slight bubbling of nitrogen is maintained in this solution called B.

After the 30 minutes of reflux, 5% by weight of solution B are introduced into the first reactor and wait until the pH rises to around 8, while keeping the latter between 7 and 8.

If the pH becomes less than or equal to 7, the introduction of solution B is stopped.

If the pH becomes greater than or equal to 8, the introduction of solution B is accelerated.

After the end of the introduction of solution B (duration 6 to 8 hours), the reaction medium is left for one hour at reflux.

The sulfur dioxide is introduced as slowly as possible and the pH is stabilized around 5.5-6.

The mixture is distilled with a stream of nitrogen while heating gradually, and the distillation is stopped when the weight of the distillate reaches 20% of the processing weight.

The dry matter content is determined by the conventional dry matter measurement technique, in the present case placing 3 g of the product obtained for 6 hours in an oven at 105 ° C. The dry matter determined at 43% is adjusted by adding water.

Treating with H₂O₂ 130 volumes if necessary so that the sodium sulfite content is less than 0.1%.

About 940 g of product 1 are finally obtained which contain at least 25% by weight of octyl-1-sulfonate constituting the majority fraction, and from 5 to 10% by weight of octyl-disulfonate.

EXAMPLE 2

In a first reactor, 61 g of C₆ α-olefin, 142 g of C₈ α-olefin, 171 g of isopropranol, 120 g of water and 12 g of tert-butyl perbenzoate are placed.

Heated with stirring and at reflux 76 ° C. The pressure is of the order of 1 bar for 30 minutes.

In a second reactor, 327 g of water are placed and, with stirring, 164 g of sodium metabisulfite are placed, then 45 g of sodium hydroxide solution.

After dissolution, this solution called B is left under nitrogen bubbling.

After the 30 minutes of reflux, 5% by weight of solution B is introduced into the first reactor and it is expected that the pH rises to 8 while maintaining the pH between 7 and 8.

If the pH becomes less than or equal to 7, the introduction of solution B is stopped.

If the pH becomes greater than or equal to 8, the introduction of solution B is accelerated.

After the end of the introduction of solution B (duration 6 to 8 hours) the reaction medium is left for one hour at reflux.

The sulfur dioxide is then introduced as slowly as possible and the pH is stabilized around 5.5-6.

The mixture is distilled with a stream of nitrogen while heating gradually, and the distillation is stopped when the weight of the distillate reaches 20% of the processing weight.

The dry matter determined at 43% (by the same conventional measurement technique, 3 g for 6 hours at 105 ° C) is adjusted by adding water.

If necessary, H traiteO₂ is treated with 130 volumes so that the sodium sulfite content is less than 0.1%.

About 100 g of product 2 are finally obtained and which contain at least 25% by weight of alkyl (C₆ or C₈) -1-sulfonate and from 5 to 10% by weight of alkyl (C₆ or C₈) -disulfonate, majority fraction consisting only of octyl-1-sulfonate.

EXAMPLE 3

In a first reactor capable of working under a pressure of 2 to 3 bars, 1073 g of C₆ α-olefin, 605 g of isopropranol, 418 g of water and 55 g of tert-butyl-perbenzoate are placed.

The mixture is heated with stirring while maintaining at reflux at 55 ° C.

In a second reactor, 1016 g of water are placed and 577 g of sodium metabisulfite are introduced with stirring, then 157 g of 30% sodium hydroxide solution.

After dissolution, a slight bubbling of nitrogen is maintained in this solution called B.

After the 30 minutes of reflux, 5% by weight of solution B are introduced into the first reactor and the temperature is brought to 75-80 ° C (therefore under pressure) until the pH rises to 8 while maintaining the latter between 7 and 8.

If the pH becomes less than or equal to 7, the introduction of solution B is stopped.

If the pH becomes greater than or equal to 8, the introduction of solution B is accelerated.

After the end of the introduction of solution B (duration 6 to 8 hours), the reaction mixture is left for one hour at the same temperature.

The sulfur dioxide is then introduced as slowly as possible and the pH is stabilized around 5.5-6.

It is then distilled at atmospheric pressure with a slight current, and the distillation is stopped when the isopropanol content in the product is less than 4%, or even lower depending on the desired flash point.

The dry matter determined at 43% (by the conventional measurement technique, 3 g for 6 hours at 105 ° C) is adjusted by adding water.

H traiteO₂ is treated with 130 volumes so that the sodium sulfite content is less than 0.1%.

About 4245 g of product 3 are finally obtained which contain at least 25% by weight of octyl-1-sulfonate constituting the majority fraction, and from 5 to 10% by weight of sodium hexyl-disulfonate.

Product 2 obtained according to the process described in Example 2 can be prepared by mixing products 1 and 3 .

• environ 17°C pour le produit 1,
• environ 7°C pour le produit 2 obtenu par le mélange 70/30 en poids des produits 1 et 3,
• environ 5°C pour le produit 3.

The products 1 , 2 , 3 have, as obtained in Examples 1, 2 and 3, that is to say in water, a crystallization temperature acceptable to a user, that is to say that they are liquid at 20 ° C and are perfectly homogeneous from:

• around 17 ° C for product 1 ,
• around 7 ° C for product 2 obtained by the 70/30 mixture by weight of products 1 and 3 ,
• about 5 ° C for product 3 .

The following example relates to formulations such as cleaning products and provides the necessary concentrations of hydrotropic compound to obtain homogeneous formulations (without solid phase) at a defined temperature provided.

EXAMPLE 4

• Alcool oxo C13 éthoxylé à 6 OE^a)   2
• Sodium métasilicate   2,4
• Sodium tripolyphosphate   2,4
• Sodium carbonate   3,2
• Agent hydrotrope N   X (cf tableau)
• Eau déionisée   qsp 100%

Composition de la formulation 5 (% poids):

• Nonylphénol 10 OEa)   10
• Tripotassiumpolyphosphate (TKPP)   10
• Agent hydrotrope N   X (cf tableau)
• Eau déionisée   qsp 100%

Composition de la formulation 6 (% poids):

• Nonylphénol 8 OEa)   4
• Phosphate trisodique   5
• Sodium métasilicate   2
• EDTA.4Na   0,2
• Agent hydrotrope N   X (cf tableau)
• Eau déionisée   qsp 100 %

Composition des formulations 7 et 8 (% poids) Formulations 7 8 -Sodium laurylbenzène sulfonate 1,1 2,2 -NaOH 5 10 -EDTA.4Na 0,2 0,4 -Agent hydrotrope N X X -Eau déionisée qsp 100 qsp 100

a) l'indice OE correspond au nombre de molécules d'oxyde d'éthylène condensées par molécule d'alcool.
Composition of formulation 4 (% Weight):

• C13 oxo alcohol ethoxylated at 6 EO ^a) 2
• Sodium metasilicate 2.4
• Sodium tripolyphosphate 2,4
• Sodium carbonate 3.2
• Hydrotropic agent N X (see table)
• Deionized water qs 100%

Composition of formulation 5 (% by weight):

• Nonylphenol 10 OEa) 10
• Tripotassiumpolyphosphate (TKPP) 10
• Hydrotropic agent N X (see table)
• Deionized water qs 100%

Composition of formulation 6 (% by weight):

• Nonylphenol 8 OEa) 4
• Trisodium phosphate 5
• Sodium metasilicate 2
• EDTA.4Na 0.2
• Hydrotropic agent N X (see table)
• Deionized water qs 100%

Composition of formulations 7 and 8 (% by weight) Formulations 7 8 -Sodium laurylbenzene sulfonate 1.1 2.2 -NaOH 5 10 -EDTA.4Na 0.2 0.4 -N hydrotropic agent X X - Deionized water qs 100 qs 100

a) the index OE corresponds to the number of molecules of ethylene oxide condensed per molecule of alcohol.

The values given in the table correspond to the percentages by weight of dry matter of the hydrotropic agent necessary for the clarification of the formulation at a temperature of a) 10 ° C, b) 25 ° C and c) 20 ° C.

The low concentrations of hydrotropic agents of the invention necessary for clarifying the formulations demonstrate their good effectiveness compared to the xylene sulfonate conventionally used.

Claims (7)

1 / Hydrotropic agent, in particular of detergent surfactant compounds, characterized in that it comprises in combination a majority fraction by weight of at least one mono-sulfonate alkyl sulfonate, having 6 to 10 carbon atoms, and a minority fraction d '' at least one alkyl sulfonate different from that of the majority fraction, and / or at least one alkylene sulfonate, having from 4 to 12 carbon atoms, mono- or poly-sulfonate, and optionally substituted with at least one another functional group different from the sulfonate group. 2 / hydrotropic agent according to claim 1, characterized in that the minority fraction comprises several alkyl sulfonates and / or alkylene sulfonates. 3 / Agent according to claim 2, characterized in that the weight concentration of the majority fraction is greater than that of the constituent of the minority fraction having the highest concentration. 4 / Agent according to claim 1, characterized in that at least one alkyl sulfonate of the majority fraction is chosen from alkyl-1-sulfonates. 5 / Agent according to claim 4, characterized in that the majority fraction comprises octyl-1-sulfonate. 6 / Agent according to claim 1, characterized in that the alkyl sulfonate and / or the alkylene sulfonate of the minority fraction is substituted by a functional group chosen from hydroxyl and sulfinate groups. 7 / detergent composition comprising a surfactant compound characterized in that it further comprises a hydrotropic agent of said surfactant according to any one of claims 1 to 6.