EP0688861A1 - Process for the preparation of anionic surfactant compositions in powder, bead or granular form and use of these compositions in cleaning and care products - Google Patents

Abstract

Prepn. of a surfactant compsn. in powder, pearl or granule forms involves mixing, while totally avoiding kneading, one or more surfactant(s) (I) with one or more absorbent filler(s) (II). (I) is used in aq. or aq. alcoholic paste form, with active material content at least 60 wt.%.

Description

The present invention relates to a process for the preparation of anionic surfactant compositions in powder, pearl or granule form and the application of these compositions, in particular in cleaning and / or maintenance products.

Anionic surfactants are frequently obtained in the form of aqueous solutions whose concentration of active materials is between 25 and 70%.

However, there is for many applications, particularly in detergency, a need for anionic surfactants in solid form, in particular in powder, in beads or in granules, having a high concentration of active materials, non-dusty and non-irritant during handling. , flowing easily, quickly soluble in water, high bulk density and moderate manufacturing cost.

It is known to manufacture surfactants in the form of granules, using an atomization technique which has the drawback of consuming a lot of energy. It is also known to prepare surfactant granules by absorption on charges and possibly by flaking. However, these techniques are difficult to use in the case of highly hydrophilic surfactants such as alkyl sulfates or sulfonates, which, because of their high hygroscopicity tend to regain moisture very easily and to re-agglomerate. This is the case, in particular, of secondary sodium alkanesulfonates, which, thanks to their excellent solubility in water, are used essentially in liquid detergents. These products are of great interest because of their good biodegradability, their excellent wetting power and their good detergent properties. But, on the one hand, they have the disadvantage, when produced in the form of concentrated wax, flakes or pastilles, of dissolving only relatively slowly in cold water, on the other hand, due to their high hygroscopicity, they tend, when prepares in the form of powders, to agglomerate quickly by absorption of water from moist air or water of crystallization of the compounds with which they are mixed.

Several recent methods describe preparations of anionic surfactants in the form of powders or granules.

FR-A-2 265 852 proposes the atomization of alkanesulfonates, in mixture with a mineral filler and of silicic acid. In this process, the quantities of mineral fillers required are greater than those of the active ingredient, so that the atomized product obtained has a reduced concentration of active ingredients.

EP-A-0 349 200 and EP-A-0 349 201 propose a technique akin to cryoscopic grinding: the concentrated, pasty anionic surfactant is cooled very strongly using carbon dioxide snow and then it is dispersed with using a propeller rotating at high speed.

EP-A-0 345 090 describes a process for the preparation of surfactants of the sodium alkylbenzenesulfonate type (ABSNa) in the form of granules from alkylbenzenesulfonic acid neutralized in situ, and absorbed on bentonite. The ABSNa / Bentonite ratio being between 1/3 and 1/8, the concentration of active material of the powder obtained is low.

It is known from EP-A-0 430 603 to prepare concentrated detergent compositions from anionic detergents and fillers which are intimately mixed to obtain a paste from which granules are made, which are then dried and ground into powder.

The process is however very difficult to implement industrially due to the tacky nature of the paste obtained, in particular when the surfactant belongs to the family of alkane sulfonates. The preparation of granules from this sticky paste is a delicate exercise, difficult to achieve beyond the scale of the laboratory, and the drying of these granules is difficult and heavy consumer of energy.

On the other hand, the flowability and the solubility of the products obtained by the process described in this patent application are not completely satisfactory.

In general, the known wet granulation techniques (cf. WA Ritschez Der Pharmazeutische Betrieb / band 7 - Die Tablette - Chap. 4: das Granulieren; Ed cantor KG) consist essentially of agglomerating powders using a liquid, serving as a binder, forming a homogeneous mixture in sufficient proportions to allow granulation.

In this case, as in the techniques of absorption of liquids on pulverulent charges, it is necessary to spray or disperse the liquid in a sufficiently fine manner to avoid the formation of lumps and not to exceed the maximum capacity of load absorption. These methods have several drawbacks: the need to use low-viscosity liquids and the limited capacity for absorbing charges lead to powders with a low concentration of active materials. On the other hand, it is essential to have effective spraying, mixing and dispersing equipment.

It is therefore with astonishment that the applicant has discovered a process which is easy to implement on an industrial scale and which makes it possible to obtain compositions of surfactants, in particular anionic, in powder, in beads or in granules, non-dusty, with high active material, fluids, not re-agglomerating by absorption of moisture and rapidly soluble in cold water.

The subject of the present invention is therefore a process for the preparation of surfactant compositions in powder, pearl or granule form, containing one or more surfactants, in particular anionic, and one or more absorbent fillers, characterized in that one or more surfactants are mixed in paste. aqueous or hydroalcoholic with a concentration by weight of active material greater than or equal to 60% with one or more absorbent filler (s), avoiding any mixing, in order to obtain a corresponding wet surfactant composition in powder, granules or pearls which, if desired, are dried according to processes known per se such as drying at a temperature less than or equal to 100 ° C., for example in a fluidized bed.

Unlike other known methods which consist in kneading the surfactant paste with the silicic filler, which leads to obtaining a paste, the present method, which proceeds to a coating of the filler around the surfactant particles, allows to obtain a product divided into fine particles directly at the outlet of the mixer.

Under preferential conditions for implementing the invention, the process described above is carried out using one or more surfactants in aqueous or hydroalcoholic paste with a concentration by weight of active material greater than or equal to 60% and having a viscosity Brookfield between 100 and 10,000 Pa.s determined at 20 ° C with a Brookfield LVT viscometer at the speed of 0.6 rpm.

• x % d'au moins un tensioactif anionique, avec 30% ≦ x ≦ 75%   (Rel.1)
• (100 - x) % d'au moins une charge absorbante, désignée C.

Preferably, the process according to the invention will be carried out using one or more anionic surfactants and one or more absorbent fillers in proportions such that compositions are obtained which contain, by dry weight:

• x% of at least one anionic surfactant, with 30% ≦ x ≦ 75% (Rel.1)
• (100 - x)% of at least one absorbent filler, designated C.

Preferably, the process which is the subject of the invention will be implemented using fillers C, characterized in that the particles constituting these fillers have an average diameter less than or equal to 100 μm, and in that their absorption capacity total A, expressed in grams, determined according to standard NFT 30-022, is greater than or equal to 50 g per 100 g of the charge or charges used, and preferably, greater than 100 g for 100 g of charges used.

The fillers are preferably chosen from the group consisting of silica, silicates of alkali or alkaline earth metals, clays, aluminosilicates, silicates and aluminosilicates of alkali and / or alkaline earth metals lamellar, also designated phyllosilicates.

ou y₁, y₂, y₃ ... représentent respectivement le pourcentage pondéral des charges C₁, C₂, C₃ ... dans ce mélange avec : $$\text{y₁ + y₂ + y₃ + ... = 100}$$

In the case where the compositions according to the invention contain more than one absorbent filler C, the absorption capacity A of this mixture of charges, C₁, C₂, C₃ ... having respectively an absorption capacity A₁, A₂, A₃ ... is equal to: $$\text{A = A₁y₁ + A₂y₂ + A₃y₃ ...}$$

or y₁, y₂, y₃ ... represent respectively the weight percentage of the charges C₁, C₂, C₃ ... in this mixture with: $$\text{y₁ + y₂ + y₃ + ... = 100}$$

By "anionic surfactant" is meant a surfactant having one or more anionic functions of the sulfate, sulfonate, carboxylate or phosphate type such as those cited in particular in Ullman's Encyclopaedia of Industrial Chemistry, 5th edition, volume A9, page 312 et seq., VCH GmbH - Weinheim - Germany 1991.

The expression "alkali or alkaline earth metals" can denote sodium, potassium, lithium, calcium, magnesium.

The invention more particularly relates to a process as defined above, characterized in that the surfactant (s) is or are anionic (s) and is or are chosen (s) from the group of secondary alkanesulfonates C₁₃-C₁₇ and C₁₀-C₁₈ alkylpolyglycolsulfates. As we have seen, the absorbent filler (s) is or are preferably chosen from the group consisting of silica, alkali or alkaline earth metal silicates, and silicates and aluminosilicates of lamellar alkali and / or alkaline earth metals.

et que la ou les charges absorbantes est ou sont tout particulièrement choisie(s) dans le groupe constitué par la silice, le silicate de magnésium, le silicate de sodium lamellaire 2 SiO₂, NaO₂, désigné commercialement SKS6®.The subject of the invention is in particular a process for preparing the compositions as defined above, characterized in that x satisfies the relation 4: $$\text{60\% ≦ x ≦ 72\%}$$

and that the absorbent filler (s) is or are very particularly chosen from the group consisting of silica, magnesium silicate, lamellar sodium silicate 2 SiO₂, NaO₂, commercially designated SKS6®.

The surfactant compositions in granules, powder or pearls obtained by the process according to the invention may contain water or a mixture of water and an alkanol as well as the conventional additives making it possible to improve or modify the appearance, flow properties or any other property of the product, for example: additional silicic filler, dyes, perfumes, polymers, alkali silicates, etc., and they can also be mixed with fillers or other products in powder in order to obtain products intended for various applications: washing powders, cleaning products, phytosanitary products, disinfectants, etc ...

The anionic surfactant compositions in powder, granule or pearl form obtained by the process of the invention, due to their high concentration of surfactants, exhibit very advantageous properties in the fields of detergency, hygiene, agriculture, etc ... They allow easy preparation of various formulations of powdered products such as washing powder, various maintenance products, phytosanitary products, disinfectants. They are easily dispersible or soluble in water, they give quickly flowing powders and do not give resistant lumps.

A subject of the invention is finally the surfactant compositions in granules, powder or pearls obtained by a above process, as well as their use in the preparation of washing powders, cleaning products, disinfectants or phytosanitary products.

• HOSTAPUR® SAS 60 désigne un mélange d'alcanesulfonates de sodium secondaires en C₁₃-C₁₇ en solution aqueuse à 60 % en poids, commercialisé par la demanderesse.
• HOSTAPUR® SAS 93 désigne un mélange d'alcanesulfonates de sodium secondaires en C₁₃-C₁₇ cireux à 93 % en poids et 7 % d'un mélange de sulfate de sodium, d'alcanes en C₁₃-C₁₇ et d'eau, commercialisé par la demanderesse.
• AMBOSOL® C désigne un silicate de magnésium commercialisé par la demanderesse.
• SKS 6 désigne un silicate de sodium lamellaire, 2 SiO₂, NaO₂, commercialisé par la demanderesse.
• GENAPOL® LRO désigne un mélange de sels de sodium de poly(oxy-1,2 éthanediyl) α-sulfo ω-dodécyloxyle en pâte à 69 % dans l'eau, commercialisé par la demanderesse.

The following examples illustrate the present invention. The products used in the examples are defined below:

• HOSTAPUR® SAS 60 designates a mixture of C₁₃-C₁₇ secondary sodium alkanesulfonates in aqueous solution at 60% by weight, marketed by the applicant.
• HOSTAPUR® SAS 93 designates a mixture of waxy C₁₃-C₁₇ secondary sodium alkanesulfonates at 93% by weight and 7% of a mixture of sodium sulfate, C₁₃-C₁₇ alkanes and water, marketed by the plaintiff.
• AMBOSOL® C designates a magnesium silicate marketed by the applicant.
• SKS 6 denotes a lamellar sodium silicate, 2 SiO₂, NaO₂, marketed by the applicant.
• GENAPOL® LRO designates a mixture of sodium salts of poly (1,2-oxy-ethanediyl) α-sulfo ω-dodecyloxyl in paste form at 69% in water, marketed by the applicant.

• SIPERNAT® 22 commercialisé par la Société DEGUSSA AG
• MICROSIL® GP commercialisé par la Société CROSFIELD
• TIXOSIL® 38 commercialisé par la Société RHONE POULENC

The following products are precipitated silicas:

• SIPERNAT® 22 marketed by DEGUSSA AG
• MICROSIL® GP marketed by the CROSFIELD Company
• TIXOSIL® 38 marketed by RHONE POULENC

The mixtures were carried out with a SPRAY MIXER RSM6-60 laboratory mixer sold by the company TELSCHIG and whose spraying system was eliminated.

The absorption capacity of the absorbent fillers used, determined according to standard NF-T-30-022 is given in table I below. TABLE I LOADS MAXIMUM ABSORPTION CAPACITY determined according to standard NF-T-30-022 (g for 100 g of fillers) TIXOSIL® 280 AMBOSOL® 100 SKIS 6® 85 SIPERNAT® 22 260 MICROSIL® GP 320

EXAMPLES 1-8

In the mixer tank, absorbent fillers are introduced successively as well as optionally the additives such as urea, anhydrous sodium carbonate, sodium sulfate and then the anionic surfactant (s) chosen in branch or in the form of aqueous pastes of weight concentration greater than or equal to 60% in the weight proportions (expressed in grams) given in table II.

After closing, the device is rotated until the dust disappears.

• l'aspect général du mélange
• sa coulabilité
• la présence éventuelle de mottes ou d'agglomérats.

The product obtained is collected and examined. We notice :

• the general appearance of the mixture
• its flowability
• the possible presence of clods or agglomerates.

• hygroscopicité (déterminée selon la note 1)
• teneur en matières actives (titration en 2 phases selon NFT 73.258)
• extrait sec (déterminé par un séchage de 4 heures à 105°C),
• densité apparente, (déterminée selon la norme NFT 73-405),
• coulabilité mesurée selon la norme NF-T 73.008, et elle correspond à l'angle du talus d'éboulement déterminé sur un tas conique dont la base est de 100 mm de diamètre.

A fraction of the wet product is dried in a fluidized bed drier at 80 ° C for 30 minutes, then the dry product is sieved and optionally ground below 2 mm. On the product thus obtained, the following checks are then carried out and the values found are mentioned in Table II:

• hygroscopicity (determined according to note 1)
• content of active ingredients (2-phase titration according to NFT 73.258)
• dry extract (determined by drying for 4 hours at 105 ° C),
• apparent density, (determined according to standard NFT 73-405),
• flowability measured according to standard NF-T 73.008, and it corresponds to the angle of the landslide slope determined on a conical pile whose base is 100 mm in diameter.

The total absorption capacity A of the charges introduced is also determined. For this, the values measured according to the method described above and given in table I are used.

The ratio R₁ between the quantity of commercial anionic surfactants actually introduced, expressed in grams and the value A indicates, if it is greater than 1, an excess of surfactant relative to the maximum quantity capable of being absorbed by the charges.

Tables II and III clearly show that it is possible to obtain in a simple manner granular, powder or pearl compositions, having a high content of anionic active substances, easy to dry and flowing and dissolving or easily dispersing (note 2).

EXAMPLE 9 (comparative example) A) Preparation of granules according to EP-A-0 430 603

• 800 g d'HOSTAPUR® SAS 60 (introduit à une température de 60°C)
• 200 g de MICROSIL® GP
• 100 g de sulfate de sodium anhydre.

Mix in a KENWOOD CHEF mixer equipped with a planetary stirring system:

• 800 g HOSTAPUR® SAS 60 (introduced at a temperature of 60 ° C)
• 200 g of MICROSIL® GP
• 100 g of anhydrous sodium sulfate.

The components are kneaded so as to obtain a homogeneous paste, the consistency of which is analyzed using a STEVENS-LFRA TEXTURE ANALYZER device equipped with the TA9 mobile.

• 26 g sur la pâte à 60°C
• 28 g sur la pâte à température ambiante.

The load necessary to make the mobile 0.6 mm penetrate into the dough with a penetration speed of 1mm / sec is:

• 26 g on the dough at 60 ° C
• 28 g on the dough at room temperature.

These low values highlight the soft consistency of the dough.

At the outlet of the mixer, the dough brought to room temperature is extruded in a die with a diameter of 5 mm (the hot dough that is too sticky cannot be extruded) the ribbon obtained is chopped so as to obtain dumplings of approximately 5 mm of diameter.

The pellets obtained are too sticky and cannot be ground directly; nor can they be dried in a fluidized bed. They are therefore spread on a ceramic plate and dried in an oven at 105 ° C for 4 hours.

After cooling to room temperature, the dried pellets are crushed on a 2 mm then 1.25 mm sieve. This operation is difficult to perform due to the rapid fouling of the screen.

B) Preparation of the granules according to the invention

• 800 g d'HOSTAPUR® SAS 60
• 200 g de MICROSIL® GP
• 100 g de sulfate de sodium anhydre.

The SPRAY MIXER RSM 6-60 mixer is introduced separately at room temperature:

• 800 g of HOSTAPUR® SAS 60
• 200 g of MICROSIL® GP
• 100 g of anhydrous sodium sulfate.

It is rotated for 4 minutes at a speed of 60 revolutions / min.

The well-granulated and moist product is collected, the device is in no way clogged.

The product obtained was stored for one year in a closed plastic bag, at room temperature, without any degradation of its properties being noted.

The product was dried at the outlet of the mixer on a fluidized bed for 30 minutes at 80 ° C.

The crushing and sieving of the powder was carried out under the same conditions as in A. These operations were carried out without difficulty and no fouling of the sieve was observed. COMPARED PROPERTIES OF GRANULES ACCORDING TO A AND B AT B Dry extract 97.7% 99.2% Content of anionic active ingredients (NFT 73.258) 60.5% 59.2% Bulk density (NFT 73.405) 0.37 0.472 Flowability (NFT 73.008) 0.69 0.53 Solubility 1 min 91% 98% 2 mins 99% 100%

The solubility is measured at 20 ° C for 5 g of anionic active materials per liter of distilled water.

NOTES

• 1) The hygroscopicity is determined by placing in g crystallizers of 230 mm in diameter, 200 g of composition according to the invention previously dried in a fluidized bed drier at 80 ° C for 30 minutes, then by abandoning these crystallizers for 96 hours at 23 ° C in an atmosphere at 50% relative humidity and finally by determining by weight the weight of water absorbed. It is noted that the dry compositions are hygroscopic but that they do not lose their flow properties.
• 2) The speed of dissolution or of dispersion of the compositions according to the invention is determined as follows:
  - In a 2 l beaker containing 1 l of distilled water 20 ° C., P g of the composition according to the invention corresponding to 5 g of anionic active materials is poured with stirring, then the suspension obtained is kept under constant stirring. After 1 and 2 minutes, the stirring is stopped, 20 ml of the supernatant are withdrawn which is filtered on a Buchner, then the quantity of anionic surfactants dissolved according to standard NF-T-73-258 is assayed in the filtrate. The values found are given in Table III in comparison with 60% ≦ x ≦ 75% (rel.1) HOSTAPUR® SAS 93, HOSTAPUR® SAS 60 and GENAPOL® LRO paste.

Table III shows the considerable improvement in dissolution rate obtained with the compositions according to the invention compared with the usual commercial qualities.

Claims (12)

Process for the preparation of a powdered, pearl or granular surfactant composition, consisting in mixing, avoiding any kneading, one or more surfactants in aqueous or hydroalcoholic paste, having a concentration by weight of active material greater than or equal to 60%, with one or more absorbent fillers. Method according to claim 1, characterized in that, at the outlet of the mixer, the product is dried at a temperature less than or equal to 100 ° C. Method according to one of claims 1 and 2, characterized in that the surfactant paste has a Brookfield viscosity of between 100 and 10,000 Pa.s. Method according to one of claims 1 to 3, characterized in that the absorbent filler (s) C consist of particles with an average diameter less than or equal to 100 µm, and have a total absorption capacity A greater than or equal to 50 g per 100 g of charge. Process according to claim 4, characterized in that the charge (s) C are chosen from the group consisting of silica, silicates of alkali or alkaline-earth metals, clays, aluminosilicates, silicates and aluminosilicates of alkali metals and / or lamellar alkaline earth, also designated phyllosilicates. Method according to claim 4 or 5, characterized in that the total capacity for absorbing charges is greater than 100 g per 100 g of charge. Method according to one of claims 1 to 6, characterized in that the compositions obtained contain dry weight x% of at least one anionic surfactant and (100-x)% of at least one absorbent filler C, with 30% ≦ x% ≦ 75% Method according to claim 7, characterized in that: 60% ≦ x% ≦ 72%. Method according to claim 3, characterized in that the surfactant (s) are anionic and chosen from the group of C₁₃-C₁₇ secondary alkane sulfonates and C₁₀-C₁₈ alkylpolyglycolsulfates. Method according to claim 5, characterized in that the absorbent filler (s) are chosen from the group consisting of silica, magnesium silicate, lamellar sodium silicate 2 SiO₂, NaO₂, sold under the name of SKS6®. Surfactant composition in granules, powder or pearls, prepared by a process according to one of claims 1 to 10. Use of a composition according to claim 11 in the preparation of washing powders, cleaning products, disinfectants or phytosanitary products.