EP0772674B1 - Process for preparing surfactant granulates - Google Patents

Abstract

The invention concerns low dust content surfactant granulates which have increased bulk density but nevertheless dissolve well in water. These granulates can be prepared by a process in which an anionic surfactant or a plurality of anionic surfactants in its/their acid form and a highly-concentrated aqueous alkaline component are acted upon separately by a gaseous medium, are combined, neutralized in a multi-substance nozzle and, under high propellant pressure, are sprayed in a drying tower. The acid and alkaline components are combined in almost stoechiometric amounts and the resultant solid, finely particulate products are conveyed to a mechanical mixer in which the fine particles are agglomerated to form granulates having a bulk density of at least 400 g/l.

Description

The invention relates to a process for the production of washing and cleaning active Surfactant granules with high bulk density and good dissolving behavior in Water, the grain size of the granules being controllable at least in such a way that dust-free or at least low-dust granules are formed.

Surfactant granules can, for example, by conventional drying techniques of surfactant-containing solutions and pastes, especially manufactured in the spray tower will. For example, in the European patent application EP-A-0 319 819 describes a process for the production of surfactant granules by a Spray drying discloses one anionic surfactant in its acid form and one highly concentrated aqueous alkaline component separated with a gaseous Medium applied, then brought together in stoichiometric amounts, neutralized in a multi-fuel nozzle and at a high propellant pressure in Drying tower to be sprayed. The products obtained are solid or paste-like, whereby solid products are mostly relatively dusty, a relative have a high water content and a low bulk density.

Granulation is an alternative to spray drying surfactant pastes Thus describes the European patent application EP-A-0 430 148 Process for the production of fatty alcohol sulfate granules in cold water are dispersible. A highly concentrated aqueous fatty alcohol sulfate paste which less than 14% by weight water and less than 20% by weight contains further additives, mechanically at temperatures between 10 and 45 ° C processed until granules are formed. This way, though Obtain fatty alcohol sulfate granules that are already at washing temperatures between 4 and 30 ° C are dispersed; the process temperature to be included and the relatively low maximum water content of the surfactant paste, however critical process parameters. It is also not disclosed which Bulk weights which have granules produced by this process.

From European patent application EP-A-0 402 112 a method for Production of fatty alcohol sulfate and / or alkylbenzenesulfonate granules known, the neutralization of the anionic surfactants in acid form to a paste with a maximum of 12% by weight of water with the addition of auxiliaries such as polyethylene glycols, ethoxylated alcohols or alkylphenols, which one Have melting point above 48 ° C, and the granulation in a high-speed Mixer done. Again, the amount of water to be observed sets one critical process parameters. It is also not disclosed which Bulk weights which have surfactant granules obtained by this process.

From European patent application EP-A-0 402 111 a method for Production of detergent-active granules with a bulk density that are active in washing and cleaning known between 500 and 1200 g / l, a surfactant preparation form, which contains water as a liquid component and additional organic polymers and may contain builder substances, mixed with a finely divided solid and granulated in a high speed mixer. Here too the water content of the surfactant paste represents a critical process parameter If the water content of the surfactant paste is too high, the solid becomes dispersed so that it can no longer act as a deagglomeration agent. On the other hand, if the solids content exceeds a certain value, it has the mass does not have the consistency required for granulation.

The object of the invention was to develop a method that Disadvantages of the above method does not have. In particular, you should low-dust granules with increased bulk density are produced, the nevertheless have good dissolving behavior in water.

The invention accordingly relates to a method for producing Surfactant granules by spray drying, one or more anionic surfactants Anionic surfactants in its / its acid form and a highly concentrated aqueous alkaline Component separately charged with a gaseous medium, brought together, neutralized in a multi-component nozzle and at a high Propellant gas pressure are sprayed in the drying tower, bringing together the acidic and alkaline components in almost stoichiometric amounts and the solid, finely divided products obtained in a mechanical working mixer are transferred in which the fine particles to granules be agglomerated with a bulk density of at least 400 g / l.

The first stage of the process, spray neutralization, can be carried out, for example the teaching of the European patent application EP-A-0 319 819 can be carried out. At this point, it is expressly based on the revelation in the European Patent application EP-A-0 319 819 pointed out.

A preferred embodiment of the present invention provides that the separately charged with a gaseous medium acidic and alkaline Reactant flows via a single multi-component nozzle, for example via a 2-substance nozzle or a 3-substance nozzle, brought together and into the drying room be sprayed. It is also possible to merge the to carry out gas-charged reactant flows before the nozzle. Here it should be noted, however, that the distance of the place of the merge from the Spray device from the process conditions and the used Is dependent on material systems, but is preferably kept as small as possible, to clog the nozzle due to premature neutralization reactions to avoid. Therefore, the first-mentioned variant of the merge of the reactant streams in the nozzle are preferred, since in this case neutralization essentially in the nozzle or directly when exiting the Nozzle takes place. Of course, it is also possible that the merged acidic and alkaline reactant flows via several multi-component nozzles be sprayed into the drying room. This is particularly preferred when products are made from different types of anionic surfactants and thus different types of merged acidic and alkaline reactant streams sprayed should be.

In practicing the method of the invention, the starting materials for example using piston pumps almost dosed stoichiometrically into one or two non-modified commercially available ones Nozzle (s) or one or two spray tube (s) introduced. Right away The gaseous medium (propellant) is mixed in before the nozzle. This means that the admixing of the gaseous medium in the reactant streams before they meet in front of or in the nozzle. More technical Details on the implementation of the method, for example with regard to the Control of reaction temperatures, the flow rate of the Reactant flows or the pressure at which the reaction mixture enters the drying room is sprayed, the European patent application EP-A-0 319 819. In the context of this invention, "almost stoichiometric amounts "that the ratio of the number of acidic groups to alkaline Groups preferably in the range from 1.1: 1 to 0.8: 1 and in particular from 1: 1 to 0.9: 1.

As anionic surfactants in their acid form, carboxylic acids, sulfuric acid semiesters and sulfonic acids, preferably fatty acids, alkylarylsulfonic acids, α-sulfofatty acid esters as well as the sulfuric acid semiesters of if necessary alkoxylated, especially ethoxylated alcohols and fatty alcohols and / or the sulfosuccinic acid can be used. In the broadest sense, too Fatty acid esters, especially fatty acid methyl esters, are used, wherein in in this case not a neutralization reaction, but a saponification of the ester group is carried out.

Suitable anionic surfactants in their acid form are therefore in particular either an anionic surfactant in its acid form or a mixture of the group of anionic surfactants in their acid form, optionally in combination with nonionic, amphoteric and / or cationic surfactants. Preferred anionic surfactants in their acid form are C ₈ -C ₂₂ alkylsulfonic acids, C ₉ -C ₁₃ alkylbenzenesulfonic acid, usually called dodecylbenzenesulfonic acid, and methyl α-sulfofatty acid in their acid form. Particularly preferred alkyl sulfonic acids are the sulfuric acid monoesters from primary alcohols of natural and synthetic origin, in particular from fatty alcohols, e.g. B. coconut fatty alcohols, tallow fatty alcohols, oleyl alcohols, lauryl, myristyl, palmityl or stearyl alcohol, or the C ₁₀ -C ₂₀ oxo alcohols, and those secondary alcohols of this chain length. The sulfuric acid monoesters of the alcohols ethoxylated with 1 to 6 mol of ethylene oxide, such as 2-methyl-branched C ₉ -C ₁₁ alcohols with an average of 3.5 mol of ethylene oxide, are also suitable. In particular, esters of α-sulfofatty acids (ester sulfonic acids) obtained by sulfonating the methyl esters of fatty acids of plant and / or animal origin with 10 to 20 C atoms in the fatty acid molecule, for example the α-sulfonated methyl esters of the hydrogenated coconut and palm kernels, are obtained by the process according to the invention - or tallow fatty acids, and the α-sulfofatty acids (diacids) obtainable by ester cleavage. The use of mixtures of monoacids and diacids with other anionic surfactants in their acid form, for example with alkylbenzenesulfonic acids and / or fatty alkylsulfonic acids, is also preferred.

Also suitable are alkanesulfonic acids which can be obtained from C ₁₂ -C ₁₈ alkanes by sulfochlorination or sulfoxidation.

Even in the spray neutralization step, other ingredients can be used are used, which are preferably derived from the group of ingredients, usually in spray-dried washing or cleaning agents be used. In particular nonionic surfactants come, but also Builder substances such as phosphates and zeolites or polycarboxylic acids or their Salts and polymeric polycarboxylates and inorganic salts such as carbonates, Bicarbonates, silicates, sulfates and bisulfates into consideration. Solid substances can be blown into the spray drying room, for example, while for liquid components there is also the possibility of combining them with one of the reactant streams in the spray drying room. Another option is to add additional anionic surfactants and / or nonionic, surfactant pastes in addition to the reactant streams into the spray drying room. In a preferred embodiment The invention therefore uses an anionic surfactant in its acid form or a mixture from anionic surfactants in their acid form in combination with anionic, nonionic, amphoteric and / or cationic surfactants used.

As anionic surfactants, which are introduced into the process in particular in paste form can be, all are concordant to the acid forms mentioned above Salts.

Nonionic surfactants preferably used in combination with these anionic surfactants in acid form are derived from liquid alkoxylated, advantageously ethoxylated, in particular primary alcohols with preferably 9 to 18 carbon atoms and an average of 1 to 40 moles of ethylene oxide per mole of alcohol in which the alcohol residue is linear or can be methyl-branched in the 2-position, or can contain linear and methyl-branched radicals in the mixture, as are usually present in oxo alcohol radicals. However, linear residues of alcohols of native origin with 12 to 18 carbon atoms, such as, for example, coconut oil, tallow oil or oleyl alcohol, are particularly preferred. The degrees of ethoxylation given represent statistical averages, which can be an integer or a fraction for a specific product. Alcohol ethoxylates with a narrow homolog distribution (narrow range ethoxylates, nre) are also suitable. In particular, alcohol ethoxylates are preferred which have an average of 2 to 8 ethylene oxide groups. The preferred ethoxylated alcohols include, for example, C ₉ -C ₁₁ oxo alcohol with 7 E0, C ₁₃ -C ₁₅ oxo alcohol with 3 E0, 5 E0 or 7 E0 and in particular C ₁₂ -C ₁₄ alcohol with 3 E0 or 4 E0, C ₁₂ -C ₁₈ alcohols with 3 E0, 5 E0 or 7 E0 and mixtures thereof, such as mixtures of C ₁₂ -C ₁₄ alcohol with 3 E0 and C ₁₂ -C ₁₈ alcohol with 5 E0. In addition, alcohols are preferred which have more than 10 E0 per molecule of alcohol, for example 11 E0, 14 E0, 20 E0, 25 E0, 30 E0 or even 40 E0 such as tallow fatty alcohol with 40 E0. As nonionic surfactants, alkyl glycosides of the general formula R-0- (G) _x , in which R is a primary straight-chain or aliphatic radical which is methyl-branched in the 2-position and has 8 to 22, preferably 12 to 18, carbon atoms, G is a symbol , which stands for a glycose unit with 5 or 6 carbon atoms, and the degree of oligomerization x is between 1 and 10, preferably between 1 and 2 and in particular is significantly less than 1.4.

The neutralization or saponification reaction is preferably concentrated aqueous alkaline solutions, for example solutions of hydroxides, Carbonates or hypochlorites of sodium or potassium, in particular carried out with a concentrated aqueous sodium hydroxide solution and / or potassium hydroxide solution, concentrations around 45 to 55% by weight are particularly preferred. A further dilution of the reactant streams with water is not necessary.

The gaseous medium (propellant) is particularly suitable compared to the initial and end products are inert gases such as air or nitrogen. In principle is steam is also suitable, especially if one of the reactant streams or the reactant streams are heated prior to merging should).

Within the scope of this invention, only fixed should be in this first stage of the process Products are made. These are relatively dusty, and show relatively poor flow properties and in particular a high time setting and thus a low storage stability and have a relative high water content of, for example, above 5 to 15% by weight and a low bulk density of, for example, 200 to 350 g / l.

These solid products can now be transferred to any of the known mechanically operating mixers or granulators, with the aid of which the powders can be granulated and, at the same time, compacted to bulk densities of at least 400 g / l, preferably of about 420 to 650 g / l. Such mixers are, for example, ploughshare mixers or ring-layer mixers, such as those sold by Lödige, Imcatec or Drais, but also types of mixers from Schugi (Flexomix ^(R) ) or Niro (ZigZag mixer ^(R) or HEC granulator ^(R) ). Both batch and continuous mixer types can be used, with the continuously operating mixer types being preferred.

If the chemical composition and the water content of the end product are specified this granulation is carried out at a temperature at which the solid products softened and can thus be shaped. In the lower temperature range This leads to the formation of granules with only a slightly increased Bulk density; however, this increases at higher temperatures. At too high temperatures however, there is too much softening of the granules to be granulated Mix and thus to clog the mixer due to pasty caking Walls and tools. Moves at a given chemical composition the preferred temperature range also increases with increasing water content downward.

Depending on the optimal granulation conditions, drying may be necessary or humidification, cooling or heating of the spray-neutralized product be advantageous before or during granulation.

In a preferred embodiment of the invention, the spray-neutralized Powder before granulation of a treatment in a fluidized bed subjected, whereby the powders can be dried and / or cooled. Advantageously is cooling or first drying and then then cooling the products, preferably such Product temperatures can be set, which in the granulation as favorable have proven so that direct processing of the product is possible becomes.

In a further preferred embodiment of the invention, the Spray room even produce powdered products directly, i.e. without intermediate storage and without treatment in the fluidized bed in the mechanically working Mixer processed.

It has proven to be particularly advantageous if the granulation in the mixer at product temperatures between 30 and 80 ° C, preferably between 40 and 70 ° C is carried out. It is possible incorporate solid and / or liquid additional components in this process stage, however, it is not required. It was particularly surprising that the granulation of the dusty products without the addition of liquid components, which usually have to be added as a granulating liquid. On the contrary, it becomes advantageous without the addition of liquid components receive low-dust granules with controllable grain size and high bulk density, which also show a very good flow behavior, so that a Granulation of the spray-dried powder without the addition of liquid components represents a preferred embodiment.

Without wishing to commit to this theory, the applicant assumes that the relatively high water content of the sprayed and dusty products the first stage of the process serves as a "liquid reserve", whereby a Granulation is made possible. The parameter that is in the first stage of the process to the manifold disadvantages of powdered Products leads to particularly advantageous after the second stage of the process Products are created.

If desired, you can of course at this point as in conventional Granulations usually involve other additives, even at these temperatures liquid to pasty additives such as non-ionic surfactants (see above), however anionic surfactant pastes (see above) can also be added.

To worsen the time hardening of the granular end products prevent it in many cases, especially when liquid components be added during granulation and the proportion of added Liquid components preferably exceed 5% by weight, further solids, advantageously Add usual ingredients of washing or cleaning agents. The builder substances already mentioned come primarily here and inorganic salts. Additives are particularly preferred but also peroxy bleaching agents such as perborate and percarbonate, but also conventional ones Graying inhibitors and substances that prevent the re-soiling of the tissue prevent. Enzymes can also be granulated at this stage; it However, it is preferred to add these to the end product in granular form. Water and aqueous solutions are less preferred at this point: once As stated above, the water is not required as a granulating liquid and on the other hand, a subsequent drying would have to be connected in most cases which is not preferred. Such drying of the granules and thus a concentration of the granules following the In principle, however, a second process stage can be used, for example in a so-called Long-term dryer, for example in a fluidized bed or a vacuum dryer, be performed. Just like drying, there is also cooling the granules in question, as is known from the prior art. Farther can be common processing steps such as screening and, if necessary Connect the return of fine and coarse particles in the mixer.

In particular finely divided solids, for example zeolites, in particular Zeolite A and / or Zeolite P, silicates, silicas, sulfates, calcium stearates and mixtures of these advantageously become the end of the granulation step added to improve the storage stability of the granules.

In a preferred embodiment of the invention are used as solid additional components also soaps, alkyl sulfates and / or fatty acid isethionates in the Granulation stage added. It has been shown that the dissolving behavior of the Granular end products according to the invention in water, which per se already have good values, by adding these solids, for example in Amounts of 0.5 to 15 wt .-%, preferably in amounts of 1 to 10 wt .-%, yet can be increased.

The products obtained in accordance with the invention which are rapidly soluble in water are one low-dust granules. The grain sizes or certain grain size ranges are about the process parameters of the mechanically operating mixers used or granulators controllable. There are preferably bulk weights between 400 and 600 g / l and grain size ranges set, with less than 5 % By weight of a particle diameter below 0.1 mm and at least 85% by weight have a maximum particle diameter of 1.6 mm.

In a particularly preferred embodiment of the invention, surfactant granules are produced with the following composition, which more than 40 wt .-%, preferably 50 to 95 wt .-% and in particular 80 to 90 wt .-% anionic surfactants, preferably C ₈ -C ₂₂ Alkyl sulfates, in particular C ₁₂ -C ₁₈ alkyl sulfates, C ₁₆ -C ₁₈ alkyl sulfates or cuts with higher proportions of C ₁₂ and C ₁₄ .

Examples

In Examples 1 to 6, analogously to the disclosure of EP-A-0 319 819, half-sulfuric acid (FAS1 and FAS2) were spray-neutralized with 50% by weight sodium hydroxide solution via a multi-component nozzle. The spray-neutralized products FAS1 and FAS2 obtained had the composition given below (Table 1). In Examples 2 to 6, the spray-neutralized, relatively dusty products were transferred directly, that is to say without intermediate storage, to the mixers specified below. In all examples 2 to 6, granules with a bulk density of at least 400 g / l were produced which had good dissolving behavior in water. Composition of the spray-neutralized products: Examples 1, 2, 3 Examples 4, 5, 6 Balance fatty alkyl sulfates FAS 1 Balance fatty alkyl sulfates FAS 2 (C chain cut: (C chain cut: 2% by weight of C ₁₂ , C ₁₄ 24% by weight of C ₁₂ , C ₁₄ 29% by weight of C ₁₆ 23% by weight of C ₁₆ 69% by weight C ₁₈ ) 54% by weight C ₁₈ ) 2.0% by weight sodium sulfate 2.0% by weight sodium sulfate 1.5% by weight sodium hydroxide 1.5% by weight sodium hydroxide 5.0% by weight unsulfated fatty alcohol 4.0% by weight of unsulfated fatty alcohol Water like in Water like in Table 2 indicated Table 2 indicated Properties of products 2 to 6 compared to 1 Examples 1 2nd 3rd 4th 5 6 spray neutralized powder granular end product ex ploughshare mixer ex ring layer mixer FAS type FAS1 FAS1 FAS1 FAS2 FAS2 FAS2 Bulk density in g / l 310 480 520 402 475 405 Grain size distribution: to 1.6 mm 4.2 9.2 4.3 7.3 0.5 0.8 mm 8.1 13.7 8.5 9.3 8.9 0.4 mm 29.1 33.7 33.1 30.2 33.4 0.2 mm 8th 37.6 32.8 35.9 36.8 33.6 0.1 mm 41.3 18.5 10.0 16.2 14.0 22.7 underneath 50.7 2.5 0.6 2.0 2.4 0.9 Granulation parameters: K onti K K K B atch B B average residence time in minutes 1 2nd 1.5 1.5 <0.5 Temperature in ° C 60 60 35 46 32 Water content in% by weight 6 5 5 4.5 4.5 5.5 Outlet diameter in m 3.1 0.4

Example 1 was repeated with the FAS 2 type. Composition, Bulk weight and grain size distribution were in the same size range as at FAS 1.

Examples 2 and 3 (Table 2) show the effects of the residence time on the grain size distribution and the bulk weight.

Examples 4 and 5 show the effects of the granulation temperature on the bulk weight.

The improved flow properties of the products produced according to the invention 2 to 6 are one at the value of the required outlet diameter Bunkers readable: For the perfect further processing of a relative dusty, only spray-neutralized product according to Example 1 after storage in a bunker this should have an outlet diameter of 3.1 m, while for products according to one of the examples 2 to 6 outlet diameter of less than 1 m are sufficient.

Claims (12)

1. A process for the production of surfactant granules by spray drying in which an anionic surfactant or several anionic surfactants in itsltheir acid form and a highly concentrated aqueous alkaline component are separately exposed to a gaseous medium, combined, neutralized in a multicomponent nozzle and sprayed in a drying tower under a high propellent gas pressure, characterized in that the acidic and alkaline components are combined in substantially stoichiometric quantities and the solid fine-particle products obtained are transferred to a mechanical mixer in which the fine particles are agglomerated to granules with a bulk density of at least 400 g/l.
2. A process as claimed in claim 1, characterized in that, before granulation, the spray-neutralized powder is subjected to a treatment in a fluidized bed in which the powders may be dried and/or cooled, preferably cooled, or are first dried and then cooled.
3. A process as claimed in claim 1, characterized in that the powder-form products produced in the spray drying tower are further processed in the mechanical mixer without storage.
4. A process as claimed in any of claims 1 to 3, characterized in that granulation in the mixer is carried out at product temperatures of 30 to 80°C, preferably between 40 and 70°C.
5. A process as claimed in any of claims 1 to 4, characterized in that the spray-dried powder is granulated in the absence of liquid components.
6. A process as claimed in any of claims 1 to 5, characterized in that the spray-dried powder is granulated with solid added components.
7. A process as claimed in claim 6, characterized in that soaps, alkyl sulfates and/or fatty acid isethionates are used as solid added components in the granulation stage.
8. A process as claimed in any of claims 1 to 7, characterized in that fatty acids, alkylarylsulfonic acids, such as C_9-13 alkyl benzenesulfonic acid, α-sulfofatty acid esters and the sulfuric acid semiesters of optionally alkoxylated, more particularly ethoxylated, alcohols and fatty alcohols and/or sulfosuccinic acid are used as the anionic surfactants in their acid form.
9. A process as claimed in any of claims 1 to 8, characterized in that an anionic surfactant in its acid form or a mixture from the group of anionic surfactants in their acid form is used in combination with anionic, nonionic, amphoteric and/or cationic surfactants.
10. A process as claimed in any of claims 1 to 9, characterized in that, in the spray neutralization step, the ratio of the number of acidic groups to the number of alkaline groups is in the range from 1.1:1 to 0.8:1 and preferably in the range from 1:1 to 0.9:1.
11. A process as claimed in any of claims 1 to 10, characterized in that bulk densities of 400 to 600 g/l and particle size ranges where less than 5% by weight of the particles are smaller than 0.1 mm in diameter and at least 85% by weight of the particles are at most 1.6 mm in diameter are adjusted.
12. A process as claimed in any of claims 1 to 11, characterized in that surfactant granules containing more than 40% by weight, preferably 50 to 95% by weight and more preferably 80 to 90% by weight of anionic surfactants, preferably C_8-22 alkyl sulfates, more particularly C_12-18 alkyl sulfates, C_16-18 alkyl sulfates or cuts with relatively high proportions of C₁₂ and C₁₄ are produced.