EP0758374B1 - Heterogeneous surface-active granulates - Google Patents

Description

Field of the Invention

The invention relates to heterogeneous surfactant granules with a inner grain consisting of longer chain alkyl sulfates or their mixtures with shorter-chain homologues or alkyl ether sulfates and a coating of shorter chain alkyl sulfates. Another object of the invention is a method directed to the production of the heterogeneous surfactant granules.

State of the art

Anionic surfactants, especially alkyl sulfates or fatty alcohol sulfates, represent important components of washing, rinsing and cleaning agents. In contrast to non-ionic Surfactants that have an inverse solubility behavior and due to hydrogen bonding in cold water are more soluble than in warm, anionic behave Conventional surfactants, i. H. their solubility increases by Reaching the solubility product more or less linear with the temperature too. For technical applications - for example with regard to the induction capacity during the Washing process - however, there is a need for anionic Surfactants that are adequate even in cold water Possess solubility.

a) die Mitverwendung von Hydrotropen und

b) die Oberflächenvergrößerung des Tensidkorns.

In the past, there has been no lack of attempts to improve the problem of the poor solubility in cold water of anionic surfactants, in particular of alkylbenzenesulfonates, fatty alcohol sulfates and α-methyl ester sulfonates. Two main concepts were pursued, namely

a) the use of hydrotropes and

b) the surface enlargement of the surfactant grain.

The best-known hydrotropes undoubtedly include the short-chain alkylarylsulfonates, such as, for example, toluene, xylene or cumene sulfonate. They are suitable, for example, as solubilizers for anionic and nonionic surfactants in the production of liquid detergents. The improved solubility is probably due to advantageous mixed micelle formation. In this context, please refer to H.Stache's overview of fats, soaps, paints. 71 381 (1969) .

The improvement of cold water solubility, especially of Fatty alcohol sulfates, however, are usually achieved by as hydrotropic surfactants with high HLB values, for example highly ethoxylated polyglycol ethers (tallow alcohol 40 EO adduct) or the like. The achievable in this way Dissolution rates especially with fatty alcohol sulfates however, are for a variety of technical Applications unsatisfactory.

A completely different approach to improving the solubility of anionic surfactants is described in German patent application DE-A1 4030688 (Henkel). It is proposed here to dry aqueous surfactant pastes using hot steam. Condensation of the superheated steam on the cooler feed and release of the heat of condensation to the material to be dried results in the surfactant droplets heating up spontaneously to the boiling point of the water. As a result, a multitude of fine channels form in the tenside grain when the water escapes. The resulting high internal surface area - for example compared to conventional spray-dried products - leads to a significantly improved dissolution rate. Nevertheless, there is the disadvantage that the method described is associated with a high level of technical complexity.

According to the teaching of DE-A1 4124701 (Henkel), solid detergents with high bulk density and improved solubility are obtained by adding mixtures of anionic and nonionic surfactants to polyethylene glycol ethers with a molecular weight in the range from 200 to 12,000, preferably 200 to 600, and then drying and / or in solid form. According to embodiment 1, a detergent preparation containing C _12/18 fatty _alcohol sulfate, C _{12/18 fatty} alcohol 5 EO / C _16/18 tallow fatty alcohol 5 EO adduct and - based on the nonionic surfactants - not less than 45% by weight .-% polyethylene glycol with a molecular weight of about 400 disclosed, which is extruded after homogenization and processed into granules. However, the rate of dissolution of the resulting solid detergents is still unsatisfactory. In addition, the presence of the large amounts of polymer required is not desirable.

According to EP-A2 0208534 , spray-dried detergent compositions are disclosed in general form which, in addition to anionic surfactants, contain nonionic surfactants, polyacrylates and polyethylene glycol ethers with an average molecular weight in the range from 1,000 to 20,000. The teaching of this document is that the dispersibility of anionic surfactants can be improved by adding nonionic surfactants, polyethylene glycol ethers and polyacrylates to them.

DE-OS 2124526 relates to detergent and cleaning agent mixtures with controlled foam behavior . According to Example 6, compositions are disclosed which contain tallow alcohol sulfate, alkylbenzenesulfonate and polyethylene glycol with a molecular weight of approximately 20,000.

We would like to make only a marginal reference to further process developments relating to the production of solid anionic surfactants. For example, solid detergents are known from international patent application WO 92/09676 (Henkel), which are obtained by treating aqueous alkyl sulfate pastes with soda and zeolites and then extruding them. The document does not reveal anything about the dissolution rate of the solids.

From the international patent application WO 93/15180 a method for the production of solid detergents and cleaning agents for end users is known, which is characterized by a special bulk density and an improved dissolution rate.

Such detergents and cleaning agents are by Homogenization of the ingredients in a blender and subsequent treatment with additives such as Fatty alkyl sulfates produced. A lesson on targeted Structuring a surfactant grain and its advantages is the Document cannot be removed.

The object of the invention has now been to create new forms of offer of alkyl sulfates to provide which are light colored even after mechanical compression and in show improved solubility in cold water.

Description of the invention

a) Alkylsulfate der Formel (I) R¹O-SO₃X   (I) in der R¹ für einen Alkylrest mit 16 bis 18 Kohlenstoffatomen und X für ein Alkali- oder Erdalkalimetall, Ammonium, Alkylammonium, Alkanolammonium oder Glucammonium steht, und ggf.

b1) Alkylsulfate der Formel (II), R²O-SO₃X   (II) in der R² für einen Alkylrest mit 12 bis 14 Kohlenstoffatomen steht und X die oben genannte Bedeutung besitzt, und/oder

b2) Alkylethersulfate der Formel (III) R³O(CH₂CH₂O)_nSO₃X   (III) in der R³ für einen Alkylrest mit 16 bis 18 Kohlenstoffatomen, n für Zahlen von 1 bis 3 steht und X die oben genannte Bedeutung besitzt,

sowie einem Überzug, bestehend aus Alkylsulfaten der Formel (II), mit den Maßgaben, daß das Gewichtsverhältnis der Komponenten a) und b) im inneren Korn 100 : 0 bis 30 : 70, vorzugsweise 90 : 10 bis 70 : 30 und das Gewichtsverhältnis von innerem Korn zu Überzug 99,5 : 0,5 bis 90 : 10 beträgt.The invention relates to heterogeneous surfactant granules consisting of an inner grain

a) alkyl sulfates of the formula (I) R ¹ O-SO ₃ X (I) in which R ^{1 represents} an alkyl radical having 16 to 18 carbon atoms and X represents an alkali or alkaline earth metal, ammonium, alkylammonium, alkanolammonium or glucammonium, and if appropriate

b1) alkyl sulfates of the formula (II) , R ² O-SO ₃ X (II) in which R ^{2 represents} an alkyl radical having 12 to 14 carbon atoms and X has the meaning given above, and / or

b2) alkyl ether sulfates of the formula (III) R ³ O (CH ₂ CH ₂ O) _n SO ₃ X (III) in which R ^{3 represents} an alkyl radical having 16 to 18 carbon atoms, n represents numbers from 1 to 3 and X has the meaning given above,

and a coating consisting of alkyl sulfates of the formula (II) , with the provisos that the weight ratio of components a) and b) in the inner grain is 100: 0 to 30:70, preferably 90: 10 to 70:30 and the weight ratio of inner grain to coating is 99.5: 0.5 to 90:10.

In extensive investigations, the applicant has determined that the solubility behavior of tallow alkyl sulfates, which have a particularly advantageous washing power, through a defined proportion of shorter-chain homologues can be significantly improved without this Reduction in washing performance is associated. She also found that the structuring of the surfactant grain into areas longer and shorter chain alkyl sulfates, which are characterized by hydrophobic Structure breakers are separated from each other, the solubility further improved. All of these findings are the subject a number of previously unpublished patent applications. The new teaching now consists in the surprising finding that a structured, i.e. heterogeneous alkyl sulfate grain can then be obtained with further improved solubility if you have an inner grain, which is the longer chain Alkyl sulfate, optionally in a mixture with shorter-chain ones Contains homologues or selected alkyl ether sulfates Granulation with a coating of a short chain alkyl sulfate defined layer thickness.

a) 30 bis 100, vorzugsweise 70 bis 90 Gew.-% Alkylsulfate der Formel (I) R¹O-SO₃X   (I) in der R¹ für einen Alkylrest mit 16 bis 18 Kohlenstoffatomen und X für ein Alkali- oder Erdalkalimetall, Ammonium, Alkylammonium, Alkanolammonium oder Glucammonium steht, und ggf.

b1) 0 bis 70, vorzugsweise 10 bis 30 Gew.-% Alkylsulfate der Formel (II), R²O-SO₃X   (II) in der R² für einen Alkylrest mit 12 bis 14 Kohlenstoffatomen steht und X die oben genannte Bedeutung besitzt, und/oder

b2) 0 bis 70, vorzugsweise 10 bis 50 Gew.-% Alkylethersulfate der Formel (III) R³O(CH₂CH₂O)_nSO₃X   (III) in der R³ für einen Alkylrest mit 16 bis 18 Kohlenstoffatomen, n für Zahlen von 1 bis 3 steht und X die oben genannte Bedeutung besitzt,

in einem Mischapparat mit Trockungsvorrichtung mit einer wäßrigen Paste eines Alkylsulfates der Formel (II) dergestalt coatet, daß sich ein Gewichtsverhältnis zwischen innerem Tensidkorn und Überzug von 99,5 : 0,5 bis 90 : 10 einstellt.The invention further relates to a process for the preparation of heterogeneous surfactant granules, in which a dry anionic surfactant powder is obtained

a) 30 to 100, preferably 70 to 90% by weight of alkyl sulfates of the formula (I) R ¹ O-SO ₃ X (I) in which R ^{1 represents} an alkyl radical having 16 to 18 carbon atoms and X represents an alkali or alkaline earth metal, ammonium, alkylammonium, alkanolammonium or glucammonium, and if appropriate

b1) 0 to 70, preferably 10 to 30% by weight of alkyl sulfates of the formula (II) , R ² O-SO ₃ X (II) in which R ^{2 represents} an alkyl radical having 12 to 14 carbon atoms and X has the meaning given above, and / or

b2) 0 to 70, preferably 10 to 50% by weight of alkyl ether sulfates of the formula (III) R ³ O (CH ₂ CH ₂ O) _n SO ₃ X (III) in which R ^{3 represents} an alkyl radical having 16 to 18 carbon atoms, n represents numbers from 1 to 3 and X has the meaning given above,

in a mixer with a drying device coated with an aqueous paste of an alkyl sulfate of the formula (II) in such a way that a weight ratio between the internal surfactant grain and the coating is from 99.5: 0.5 to 90: 10.

Alkyl sulfates and alkyl ether sulfates

The sulfation products are among alkyl sulfates and alkyl ether sulfates primary alcohols or their ethylene oxide adducts to understand.

For the purposes of the invention, longer-chain components come as component a) Alkyl sulfates with 16 to 18 carbon atoms are considered have particularly advantageous washing properties. Typical Examples include cetyl sulfate and steryl sulfate and preferably tallow alkyl sulfate or technical mixtures comparable composition.

In the simplest case, component a) can be 100% by weight make out inner grain. However, a mixture is preferred used in addition to component a) either shorter-chain Alkyl sulfates with 12 to 14 carbon atoms (component b1) and / or alkyl ether sulfates with 16 to 18 carbon atoms and 1 to 3, preferably about 2, ethylene oxide units (Component b2). Such mixtures used, the weight ratio is between the components a) and b) usually in the range from 70:30 to 98 : 2 and is preferably 80:20 to 90:10.

The coating of the inner grain again consists of shorter-chain ones Alkyl sulfates with 12 to 14 carbon atoms. Typical Examples are lauryl sulfate, myristyl sulfate or technical Mixtures based, for example, on a coconut fatty alcohol cut. The granulation is done in such a way performed that a coating with a layer thickness accordingly 0.5 to 10, preferably 1 to 5 and in particular 1.5 to 2 wt .-% based on the granules results.

Dry surfactant powder

The substances that make up component a), ie the inner grain, alone or as a mixture, are used as dry powders. To produce a dry tallow alkyl sulfate powder, for example, an aqueous sulfuric acid half ester of a corresponding tallow alcohol can be subjected to spray neutralization following sulfation. It is also possible to dry a neutralized aqueous paste in a conventional spray tower or using superheated steam (see DE-A1 4124701 , Henkel). If a mixture of the C _16/18 alkyl sulfates with components b1) and / or b2) is desired as the inner grain, these can be prepared either mechanically by mixing the ingredients or by cosulfating the corresponding hydroxyl compounds. The sulfates are usually present as alkali metal salts and preferably as sodium salts.

Granulation

The granulation can be carried out in a manner known per se Mixer with drying device such as one Lödige mixers, Drais mixers, Schugi mixers or Fukai mixers or a fluidized bed continuously or discontinuously be performed.

In a first embodiment, the heterogeneous surfactant granulate is produced by coating a C _16/18 tallow alkyl sulfate powder with C _12/14 coconut alkyl sulfate using water as the granulating liquid.

In a preferred embodiment, for example Tallow alkyl sulfate powder or a powdery mixture of Tallow alkyl sulfate and lauryl sulfate or tallow alkyl 2EO sulfate (Weight ratio 90:10) with a 35 or 65 wt .-% aqueous paste coated by lauryl sulfate.

Granulation has also proven to be advantageous in such a way that particles result which predominantly, i.e. a diameter of at least 90% by weight have from 0.2 to 1.4 and preferably 0.2 to 0.8 mm. If necessary, coarse particles can be screened off.

Industrial applicability

The surfactant granules according to the invention have rapid solubility in cold as in warm water as well as an improved Washing behavior in the washing machine. Another The advantage is that in the course of their mechanical compression no adverse effects on their color quality entry.

The surfactant granules according to the invention can be combined with others Detergent ingredients mixed or agglomerated or are extruded and are accordingly suitable as Raw materials for the manufacture of solid detergents.

The following examples are intended to be the subject of the invention explain in more detail without restricting it.

Examples I. Influence of the granulating liquid Comparative Example V1:

An acidic sulfuric acid _half ester based on C _16/18 tallow alcohol was subjected to spray neutralization. The dried powdered C _16/18 tallow alcohol sulfate sodium salt was then processed with the addition of water in a Lödige mixer to form a granulate.

Comparative example V2:

An aqueous paste of C _16/18 tallow alkyl sulfate sodium salt with a solids content of about 50% by weight was subjected to drying with superheated steam. The anhydrous powder was then processed into granules with the addition of water in a Lödige mixer.

Example 1:

An acidic sulfuric acid half ester based on C _16/18 tallow alcohol and C _12/14 coconut fatty alcohol (weight ratio 90:10) was subjected to spray neutralization. The dried powdered C _{12/18 fatty} alcohol sulfate sodium salt was then processed with the addition of water in a Lödige mixer to form a granulate.

Example 2:

Comparative example V1 was repeated. Instead of water, an aqueous paste of lauryl sulfate sodium salt with a solids content of 35% by weight (Texapon ^(R) LS35, Henkel KGaA, Duesseldorf / FRG) was used. The weight ratio between the inner grain and the coating was 1.5% by weight, based on the solids content of the granulating liquid.

Example 3:

Comparative example V1 was repeated. Instead of water, an aqueous paste of lauryl sulfate sodium salt with a solids content of 35% by weight (Texapon ^(R) LS35, Henkel KGaA, Duesseldorf / FRG) was used. The weight ratio between the inner grain and the coating was 2.5% by weight, based on the solids content of the granulating liquid.

Example 4:

Comparative example V1 was repeated. Instead of water, an aqueous paste of lauryl sulfate sodium salt with a solids content of 65% by weight (Texapon ^(R) LS65, Henkel KGaA, Düsseldorf / FRG) was used. The weight ratio between the inner grain and the coating was 1.5% by weight, based on the solids content of the granulating liquid.

Example 5:

An aqueous paste of C _16/18 tallow alkyl sulfate sodium salt with a solids content of about 50% by weight was subjected to conventional spray drying. The anhydrous powder was mixed in a weight ratio of 90:10 with a spray-neutralized powder of C _12/14 cocoalkyl sulfate sodium salt and then with the addition of an aqueous paste of lauryl sulfate sodium salt with a solids content of 35% by weight (Texapon ^(R) LS35, Henkel KGaA, Düsseldorf / FRG) granulated in a Lödige mixer. The weight ratio between the inner grain and the coating was 1.5% by weight, based on the solids content of the granulating liquid.

Example 6:

Example 5 was repeated, but instead of the coconut alkyl sulfate, C _16/18 tallow alcohol 2EO sulfate sodium salt was used.

Example 7:

A spray-dried mixed powder consisting of C _16/18 tallow alkyl sulfate, C _12/14 coconut alkyl sulfate and C _16/18 tallow alcohol 1EO sulfate (each in the form of the sodium salts, weight ratio 35:25:40) was added in a Lödige mixer granulated aqueous paste of lauryl sulfate sodium salt with a solids content of 35 wt .-%. The weight ratio between the inner grain and the coating was 2% by weight, based on the solids content of the granulating liquid.

Example 8:

Example 5 was repeated, instead of the spray-dried one Tallow alkyl sulfate, however, steam-dried material used.

The particle size of all granules examined was one Proportion of at least 90% by weight in the range from 0.2 to 1.4 mm.

Description of the hand washing test.

To determine the solubility, 32 g of the granules were added Examples 1 to 8 and comparative experiments V1 and V2 dissolved in 4 liters of water (16 ° d) at 30 ° C. Then a Pillow (53 x 32 cm) made of black nickel fabric 60 s in the Fleet drummed and turned, which simulates a hand washing process shall be. The pillow is wrung out and the Let wash liquor sit for 15 s. The insoluble particles are filtered quantitatively through a sieve and the residue dried in a drying cabinet at 60 ° C to a weight concentration.

The results of the tests are summarized in Table 1 (means from duplicate determination, percentages as% by weight). Hand washing tests: Influence of the granulating liquid E.g. cTAS% cKAS% cTAES% TR GRV Approx. % -rel 1 90 10th 0 SN water 31.1 2nd 100 0 0 SN 1.5 wt% LS35 26.7 3rd 100 0 0 SN 2.5 wt% LS35 26.3 4th 100 0 0 SN 1.5 wt% LS65 26.7 5 90 10th 0 SN 1.5 wt% LS35 25.7 6 90 0 10th SN 1.5 wt% LS35 26.2 7 35 25th 40 SN 2.0 wt% LS35 30.0 8th 90 10th 0 HD 1.5 wt% LS35 25.2 V1 100 0 0 SN water 60.3 V2 100 0 0 HD water 59.8 Legend: cTAS = concentrate. Tallow alkyl sulfate in the inner grain cKAS = concentrate. Coconut alkyl sulfate " cTAES = concentrate. Tallow alcohol ether sulfate " TR = drying process SN = spray neutralization / spray drying HD = hot steam drying GRV = granulation process Approx. = Residue

II. Influence of particle size

Example 5 was repeated, but granules of different particle size distribution were produced by varying the mixer speed, mass flow and mixing time. The results are summarized in Table 2: Hand washing tests: influence of particle size E.g. Particle size distribution Residue% -rel. <0.2 mm 0.2-1.4 mm > 1.4 mm % By weight % By weight % By weight 8th 2nd 90 8th 25.7 9 1 93 6 25.1 V2 5 85 10th 28.2 V3 7 82 12th 31.0

Claims (3)

1. Heterogenous surfactant granules consisting of an inner core containing

   a) alkyl sulfates corresponding to formula (I): R¹O-SO₃X in which R¹ is an alkyl radical containing 16 to 18 carbon atoms and X is an alkali metal or alkaline earth metal, ammonium, alkylammonium, alkanolammonium or glucammonium,
   and optionally

   b1) alkyl sulfates corresponding to formula (II): R²O-SO₃X in which R² is an alkyl radical containing 12 to 14 carbon atoms and X is as defined above,
   and/or

   b2) alkyl ether sulfates corresponding to formula (III): R³O(CH₂CH₂O)_nSO₃X in which R³ is an alkyl radical containing 16 to 18 carbon atoms, n is a number of 1 to 3 and X is as defined above,

   and of a coating consisting of alkyl sulfates corresponding to formula (II), with the provisos that the ratio by weight of component a) to component b) in the inner core is 100:0 to 30:70 and the ratio by weight of inner core to coating is 99.5:0.5 to 90:10.
2. A process for the production of heterogeneous surfactant granules, characterized in that a dry anionic surfactant powder containing

   a) 30 to 100% by weight of alkyl sulfates corresponding to formula (I): R¹O-SO₃X in which R¹ is an alkyl radical containing 16 to 18 carbon atoms and X is an alkali metal or alkaline earth metal, ammonium, alkylammonium, alkanolammonium or glucammonium, and optionally

   b1) 0 to 70% by weight of alkyl sulfates corresponding to formula (II): R²O-SO₃X in which R² is an alkyl radical containing 12 to 14 carbon atoms and X is as defined above,
   and/or

   b2) 0 to 70% by weight of alkyl ether sulfates corresponding to formula (III): R³O(CH₂CH₂O)_nSO₃X in which R³ is an alkyl radical containing 16 to 18 carbon atoms, n is a number of 1 to 3 and X is as defined above,

   is coated in a mixer/dryer with a water-containing paste of an alkyl sulfate corresponding to formula (II) in such a way that a ratio by weight of inner surfactant core to coating of 99.5:0.5 to 90:10 is established.
3. A process as claimed in claim 2, characterized in that granulation is carried out in known manner in such a way that at least 90% by weight of the particles obtained have a diameter of 0.2 to 1.4 mm.