EP0662510B1 - Hydrotropic agents and compositions containing them - Google Patents

Description

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

According to the invention, by tensioactivity is meant the property of a product in solution of lowering the tension interfacial associated with an increase in the concentration of the product at the interface.

Hydrotropy means the property of a product to increase the solubility of a substance in water, without this product being a soil solvent. This property will be particularly exploited in the invention for solubilizing high concentrations of surfactant detergents in water.

A hydrotropic agent may also have tensloactive properties.

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

Indeed, although being more complex to prepare for the manufacturer, the concentrated formulations of agents are advantageous for the user, because they are more economical, less bulky, less heavy to carry. This applies equally well to liquid preparations, whether they are monophasic or multiphase, than solid preparations generally prepared from multiphase liquid preparations very concentrated.

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

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

In addition to their hydrotropic nature, solubilizing agents must meet regulatory standards concerning their toxicity and their biodegradability, as well as the wishes of users concerning in particular the impact of these agents on the environment. Thus, these agents must be little or not harmful for man 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, arylsulfonates. low molecular weight, such as benzene sulfonates, tuuene sulfonates, xylenesulfonates, cumenesulfonates, as well as short carbon chain alcohol sulfates, preferably with 8 atoms of carbon.

All of these hydrotropic agents have drawbacks.

Alcoholic solvents are mostly volatile and fall into the category of VOCs (Volatile Organic Compound) likely by their volatility to contribute to the reduction of the ozone content and to the effect Greenhouse. They are also easily flammable.

Aryl sulfonates, due to the presence of aromatic rings in their structure, are assumed lead to relatively persistent by-products 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 is described, having either 7, ie 8 carbon atoms, as hydrotropic agent, capable of being incorporated into compositions detergent. The hydrotropic nature of such agents is no longer always sufficient for detergent preparations currently marketed, very concentrated in surfactant detergent.

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

The object of the present invention is a hydrotropic agent which on the one hand has good solubility in water 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 the detergent surfactant compounds, which they be anionic, nonionic or amphoteric, has moreover surfactant properties which come complete those of the solubilized surfactant compound, which from an economic point of view is not negligible.

According to the invention, the hydrotropic agent is identical to the product capable of being obtained according to the method of Example 1, or 2, or 3 below.

Hydrotropic agents meeting the definition of the present invention have a solubilizing power often higher than that of arylsulfonates commonly used today, and therefore provide 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, in the same conditions, greater solubility, easier commercial presentation, or more concentrated, for an identical cold resistance, therefore more economical, and confer better stability of the preparations resulting at low temperature.

Another subject of the invention is a detergent composition comprising a surfactant compound and a hydrotropic agent 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 lowering the temperature, and have a low power foaming, which allows easy handling.

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

The characteristics and advantages of the present invention are now illustrated by Examples 1 to 4 below, in which Examples 1 to 3 illustrate the methods for obtaining the 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 C ₈ α-olefin, 151.2 g of isopropranol are placed; 97.2 g of water and 10.44 g of tert-butyl-perbenzoate.

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 metabisulfite of sodium then 39.7 g of 30% sodium hydroxide solution. After dissolution, a slight bubbling of nitrogen is maintained in this solution called B.

After 30 minutes of reflux, 5% by weight of solution B are introduced into the first reactor and waits until the pH rises to 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.

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

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

H ₂ O ₂ is treated with 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 C ₆ α-olefin, 142 g of C ₈ 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 30 minutes of reflux, 5% by weight of solution B is introduced into the first reactor and waits for the pH to rise to 8 while keeping 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.

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

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 ₂ O ₂ 130 volumes are treated 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 (C ₆ and C ₈ ) -1-sulfonate and from 5 to 10% by weight of alkyl (C ₆ and C ₈ ) - disulfonate.

EXAMPLE 3

In a first reactor capable of working under a pressure of 2 to 3 bars, 1073 g of C ₆ α-olefin, 605 g of isopropranol, 418 g of water and 55 g of terrio-butyl-perbenzoate are placed.

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

In a second reactor, 1,016 g of water are placed and 577 g of metabisulfite of sodium, then 157 g of 30% sodium hydroxide solution.

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

After 30 minutes of reflux, 5% by weight of solution B is introduced into the first reactor and brings the temperature 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 flash point sought.

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

H ₂ O ₂ 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 hexyl-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 phase solid) at a defined temperature provided.

EXAMPLE 4

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

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 the clarification of the formulations demonstrate their good effectiveness compared to the xylene sulfonate conventionally used.

Claims (2)

1. Hydrotropic agent, in particular for detergent surface-active compounds, comprising alkylsulfonates, characterized in that said agent is obtainable according to the process of example 1, or 2, or 3.
2. Detergent composition comprising a surface-active compound, characterized in that it additionally comprises a hydrotropic agent according to claim 1.