EP0429515A1 - Process for producing tablets of low-phosphate washing powder - Google Patents

Abstract

A laundry product is prepared in tablets, containing washing salts phosphate-free or low in phosphates, anionic surfactants and non-ionic surfactants, by first preparing two components (A) and ( B) powdery to granular, which is mixed and then compressed. Component (A) contains the total mass of anionic surfactants and component (B) contains between 75 and 100% by weight of the total mass of nonionic surfactants.

Description

 -A -

"Process for the production of reduced phosphate detergent tablets"

Detergent tablets have a number of advantages over powdered agents, such as simple dosing and low packaging volume requirements. Problems arise, however, from the fact that relatively high compression pressures have to be used to achieve sufficient dimensional and fracture resistance when pressing the powdered raw materials. Because of the high degree of compaction, tablets of this type often have inadequate disintegration and dissolving properties during use, with the result that undissolved parts remain in the washing-up compartments of the washing machines. These problems already exist with phosphate-rich, i.e. H . 50 wt. - And more of tripolyphosphate (TPP) containing tablets and was partially solved by using certain TPP modifications or. performed partial hydrolysis of the TPP; compare US 3, 081, 267, US 3, 461, 074, DE 1 1 91 509, DE 12 71 884 and DE 14 67 595 (CB 1 041 036).

Such proposed solutions are unsuitable for the production of phosphate-reduced, in particular phosphate-free tablets. Rather, there are additional problems here in that the phosphate-substituting zeolites, which are considered to be particularly environmentally friendly, are water-insoluble and hinder the disintegration of the tablet in water. An additional difficulty arises when nonionic surfactants are used, to which detergents which are to be used in modern detergents at 40 to 60 C are not used. can be pulled. It has been shown that the disintegration and dissolving process is considerably delayed if the powdery or granular mixtures intended for compression contain, in addition to zeolite, anionic surfactants in addition to nonionic surfactants. Even when additional tablet disintegrants are used, it is not possible to produce detergent tablets from such mixtures with the customary auxiliaries which are at the same time readily soluble and sufficiently break-resistant.

This problem is solved by the present invention.

The invention relates to a process for the preparation of phosphate-reduced, finely divided zeolites, skeletal salts, anionic surfactants and nonionic surfactants from the class of detergents in tablet form containing polyglycol ether derivatives, characterized in that at least two previously prepared powdery to granular components (A) and (B) mixed and this mixture pressed, the components

(A] the total amount of anionic surfactants,

(B) 75 to 100% by weight of the total amount of the nonionic surfactants.

The weight ratio of anionic surfactant to nonionic surfactant in component (A) should preferably not be less than a ratio of 10: 1.

In the context of the invention, ^{n reduced} phosphate means those agents which contain less than 10% by weight, preferably less than 5% by weight and in particular less than 1% by weight of phosphate, calculated as anhydrous pentasodium triphosphate. In a particularly preferred embodiment, the agents are phosphate-free. The compositions contain fine crystalline zeolite as a phosphate substitute in amounts of 10 to 40% by weight, preferably 20 to 35% by weight. Suitable zeolites are those of the zeolite A type. Mixtures of zeolite NaA and NaX can also be used, the proportion of the zeolite NaX in such mixtures advantageously being less than 30%, in particular less than 20%. Suitable zeolites have no particles larger than 30 μm and consist of at least 80% of particles smaller than 10 μm. Their average particle size (volume distribution, measurement method: Coulter Counter) is 1 to 10 μm. Their calcium binding capacity, which is determined according to DE 24 12 837, is in the range from 100 to 200 mg CaO / g.

The agents also contain water soluble skeletal salts with water softening or. sequestering properties. These include washing alkalis such as sodium carbonate, sodium silicates with the composition Na_0: SiO_ = 1: 1 to 1: 3, 3 and salts of polyanionic compounds from the class of the homopolymeric or copolymeric carboxylic acids, the aminopolycarboxylic acids and the polyphosphonic acids. Washing alkalis and sequestering polyanionic compounds are mostly used together.

Examples of homopolymeric and / or copolymeric carboxylic acids or. whose water-soluble salts, of which the sodium salts are preferably used, are polyacrylic acid, polymethacrylic acid and polymaleic acid, copolymers of acrylic acid with methacrylic acid or. Copolymers of vinyl methyl ether or vinyl ethyl ether, further with vinyl esters such as vinyl acetate or vinyl propionate, acrylamide, methacrylamide and with ethylene, propylene or styrene. In such copolymeric acids in which one of the components has no acid function, the proportion thereof, in the interest of sufficient water solubility, is not more than 50 mole percent, preferably less than 30 mole percent. Copolymers of acrylic acid have proven particularly suitable or methacrylic acid with maleic acid, as described in more detail, for example, in EP 25 551-B1. These are copolymers which contain 40 to 90% by weight of acrylic acid or methacrylic acid and 60 to 10% by weight of maleic acid. Copolymers in which 45 to 85% by weight are particularly preferred. -% acrylic acid and 55 to 15 wt .-% maleic acid are present. The molecular weight of the homo- or copolymeric polycarboxylates is generally 2,000 to 150,000, preferably 5,000 to 100,000.

Suitable aminopolycarboxylic acid is nitrilotriacetic acid in the form of its sodium salt. Its proportion can be up to 10% by weight, preferably up to 5% by weight. Also useful are ethylenediaminetetraacetic acid and its higher homologs, such as diethylenetriaminepentaessϊgsäure, which are also present as sodium salts. Examples of preferred polyphosphonic acids or. their salts are 1-hydroxyethane-T, 1-diphosphonate, ethylenediamine tetramethylene phosphonate and diethylenetriamine pentamethylene phosphonate, each in the form of the sodium salt. The proportion of these additives can be up to 2% by weight, generally up to 1% by weight, based on the granules.

In particular, sulfonates and fatty acid soaps, each of which is preferably present as sodium salts, have proven to be suitable anionic surfactants. Alkyibenzenesulfonates with linear C _q _ ₁ _ alkyl chains, in particular dodecylbenzenesulfonate, linear aikansulfonates with 11 to 15 C atoms, as are obtained by sulfochlorination or. Sulfoxidation of alkanes and subsequent saponification or neutralization are available, alphasulfofatty acid salts and their esters, which are derived from saturated C * - 1 - 2 .. - ₁ I ₀ o-fatty acids and lower alcohols such as methanol, ethanol and propanol derive, and olefin sulfonates, such as z. B. are formed by SO, sulfonation of C. __ _{1 R} olefins and subsequent alkaline hydrolysis. Preferred surfactants are the alkyl benzene sulfonates defined above. Suitable soaps are those of saturated and / or unsaturated C.sub .-- fatty acids, for example from coconut, palm kernel or tallow fatty acids and soaps obtained from hydrogenated rapeseed oil fatty acids. The anionic surfactants are generally in the form of sodium salts.

The total anionic surfactant content of the tablets is 3 to 20, preferably 5 to 15,% by weight. Of this amount, preferably 3 to _/ 1 ^'5 wt -.%, Particularly 5 to 10 wt .-% to sulfonate and 0 to 1 0, preferably 0. 5 to 5 and insbe¬ sondere 1 to 3 wt. -% on soap.

Suitable nonionic surfactants are alkoxylation products with 10 to 20 carbon atoms in the hydrophobic radical and 3 to 20 glycol ether groups. These include ethoxylation products of alcohols, vicinal diols, amines, thioalcohols, fatty acid amides and fatty acids. Alkylphenol polyglycoiether having 5 to 12 carbon atoms in the alkyl radical and 3 to 10 ethylene glycol ether groups can also be used. Finally, block polymers of ethylene oxide and propylene oxide, which are commercially available under the name Pluronics, are also suitable.

Preferred nonionic surfactants from the class of polyglycol ethers are derived from alcohols with 12 to 18 carbon atoms. These alcohols can be saturated or olefinically unsaturated, linear or methyl-branched in the 2-position (oxo radical). Your reaction products with ethylene oxide (EO) or propylene oxide (PO) are water-soluble or. water-dispersible mixtures of compounds with different degrees of alkoxylation. The number of EO or. PO groups correspond to the statistical mean.

Examples of suitable ethoxylated fatty alcohols are C.

Coconut alcohols with 3 to 12 EO, C. _c . _0- tallow alcohol with 4 to 16

16-18 ^{* 3} EO, ethyl alcohol with 4 to 12 EO and ethylation products of corresponding chain and EO distribution obtainable from other native fatty alcohol mixtures. From the series of ethoxylated oxo alcohols, for example those of the composition C. _, _ς with 5 to 10 EO and C _{1 ü} -C ... with 6 to 12 EO are suitable. Mixtures of low and highly ethoxylated alcohols are characterized by increased detergency against both greasy and mineral soiling, for example those made of tallow alcohol with 3 to 6 EO and tallow alcohol with 12 to 16 EO or C _τ _ ....- oxo alcohol with 5 EO and C. _. "-Oxo alcohol with 8 to 12

1 -> - 1 D 1 / - I 4

EO. Furthermore, ethoxylates are also suitable which contain EO groups and PO groups, e.g. B. C. "" alcohols of the formula R- (PO) - (EO), or R- (EO). - (PO). where a is numbers from 1 to 3,

3 D D C b mean those from 5 to 20 and c numbers from 1 to 10 (b greater than c).

The total content of non-tonic surfactants in the tablets can be 3 to 15, preferably 4 to 10,% by weight.

Optional components of the tablet-like agents are neutral salts such as sodium suifate, anti-graying agents, in particular cellulose ethers, optical brighteners, colorants and fragrances, bioeides, tableting aids, bleaching persalts such as sodium perborate (as mono- or tetrahydrate), bleach activators such as tetraacetylethylenediamine, enzymes and foam inhibitors such as organopolysiloxanes, paraffins, microcrystalline paraffins and bis-acylalkylene diamines derived from C _{1 fi} - »- fatty acids.

The tablets are manufactured in several stages. In the 1st In the first stage, at least two granular powder components (A) and (B) are produced separately from one another, which are dry-mixed in a second stage. In this mixing stage, further powdery to granular additives can also be added. These include those already mentioned Tableting aids, tablet disintegrants, persalts, bleach activators, enzymes and foam inhibitors. Liquid additives, the proportion of which is generally low, can also be mixed in at this time, such as fragrances and liquid or melted foam inhibitors. Because of their small proportion, they are easily adsorbed without impairing the pourability and tablettability of the dry mixtures.

The powder component (A) contains the total amount of the anionic surfactants used. This component can consist exclusively of anionic surfactants or a part of the zeolite or. the other scaffold salts (builder salts) as well as common detergent ingredients such as neutral salts, optical brighteners and anti-graying substances. If component (A) consists exclusively of anionic surfactants, for example alkylbenzenesulfonate or soap, these are preferably in the form of granular granules, flakes or extrudates. However, component (A) preferably contains part of the total zeolite present, the builder salts and, if appropriate, the other detergent constituents. If the powder component (A) contains zeolite, it can also have low levels of nonionic surfactants. These small amounts of nonionic surfactants in (A), which are therefore largely harmless to the solution behavior of the tablet, can be introduced together with the zeolite into the powder component if it is produced as a water-containing, stable dispersion (masterbatch). Such zeolite dispersions are often stabilized by adding nonionic surfactants, especially low ethoxylated fatty alcohols. The proportion of such nonionic surfactants is usually 1 to 5% by weight, based on anhydrous zeolite (0.5 to 2% by weight, based on aqueous zeolite dispersion). However, if component (A) contains no zeolite, it is preferably free of nonionic surfactants. If appropriate, the powder component (A) can also be divided into 2 or more individual components, for example into a partial component which contains the sulfonate surfactant and part of the other solids and a second part component which consists of soap particles. In a further embodiment, the soap particles can also be agglomerated with some of the solids.

The powder component (B) contains the main amount, preferably the total amount of the total nonionic surfactants used, and also carriers on which these nonionic surfactants are adsorbed. Suitable carriers are zeolite, the aforementioned water-soluble skeletal salts, sodium sulfate and other solids commonly used in detergents, such as cellulose ethers, in particular carboxymethyl cellulose, methyl cellulose, hydroxyalkyl cellulose and hydroxyalkyl-cellulose mixed ethers. Mixtures of the abovementioned carriers are preferably used, in particular mixtures of zeolite and sodium sulfate, mixtures of zeolite and salts of (co) polymeric carboxylic acids and, if appropriate, additionally sodium sulfate, mixtures of zeolite and cellulose ethers (this, too, if appropriate with the addition of sodium sulfate ), but in particular mixtures of all of the carriers mentioned. Furthermore, it has proven to be expedient to also incorporate the optional optical brighteners, fragrances and bio-oids into the powder component (B). If the use of higher temperatures, for example spray drying temperatures, is dispensed with in the preparation of the powder component (B), peroxy compounds such as sodium perborate (as mono- or tetrahydrate) can also be used as the carrier component.

The content of powder component (B) on the one hand and on nonionic surfactants on the other hand should be chosen so that the grains are still free-flowing and non-sticky. If necessary, the grains can be powdered on the surface to prevent sticking. Zeolites, neutral salts and cellulose ethers as well as known adsorbents, e.g. B. finely divided silica. The proportion of water-insoluble powder should 3 wt. -%, based on the powder component, not or not significantly exceed to counteract a reduction in the disintegration and dissolving properties.

The preparation of the: two powder components can be carried out in a manner known per se, for example by spray drying aqueous batches (slurries) or by mixing the individual components under granulating conditions or by compacting, for. B. Plasticizing, extruding and then comminuting the plasticized mixtures to a suitable particle size. Both powder components can be produced in the same or different ways.

The procedure is preferably such that, in the preparation of powder component (B), an aqueous batch (slurry) is first spray-dried which contains zeolite and salts of (co) polymeric carboxylic acids and, if appropriate, sodium sulfate. Optical brighteners and cellulose ethers suitable as graying inhibitors can also be used in this way. Due to their porous structure, the granular products formed during spray drying have a very high adsorption capacity for liquid or. greasy substances, especially non-ionic surfactants and also perfume oils. They are therefore sprayed or sprayed with the liquid or melted nonionic surfactants after the spray drying. mixed, whereby they can take up to 40 wt .-% of it. With this adsorption process, a desired increase in bulk density from 300 to 450 g / l to 500 to 700 g / l (grams per liter) is achieved. The preferred production method for the powder component (A) is granulation, which can be carried out continuously or in batches in conventional granulating devices. For example, the solids such as soda, sodium sulfate, sodium silicate and zeolite can be presented in dry form and the anionic surfactants in neutralized form (salt form) mixed in as aqueous solutions under granulating conditions. The excess water is removed simultaneously or in a subsequent drying process. However, the neutralized solutions of the anionic surfactants, especially those of alkylbenzenesulfonates and soaps, are pasty or highly viscous in concentrated form and must therefore be diluted with water in order to be processed. However, this requires an increased outlay on drying.

It is therefore preferable to start from the free sulfonic acids, especially pure or high-strength aqueous ones

Alkylbenzenesulfonate pastes which (if appropriate in a mixture with free fatty acids) are neutralized in the mixer with equivalent amounts or a slight excess of high-proof sodium hydroxide solution (e.g. 50% strength). For this purpose, the other solids such as sodium carbonate, sodium silicate, sodium sulfate and zeolite are mixed in, with granulation occurring at the same time as a result of mechanical processing. The zeolite can also be used as an aqueous dispersion (masterbatch). The moist granules are then dried, the proportion of moisture (corresponding to a loss of water at a drying temperature of 140 ° C.) being below 10% by weight, preferably below 5% by weight. The specified method of production favors the formation of high rubble and thus small packaging volumes without impairing the disintegration and dissolving properties.

The powder component (A) can also be coated or powdered before further processing, the ones already mentioned Fabrics can be used. This coating prevents intimate contact with the nonionic surfactants in component (B) and can thus improve or improve the disintegration and dissolving properties of the tablet. prevent the sticking of powder components on the tablet press.

The two powder components advantageously have a bulk density of 400 to 1000 g / l, preferably 500 to 900 g / l. Their average grain size is 0.2 to 1.2 mm, the proportion of particles less than 0.05 mm less than 1% by weight and that of particles more than 2 mm less than 5% by weight. -% should be.

In addition to the two mandatory components (A) and (B), further powder components can also be used. These include per compounds such as sodium perborate, which is present as a tetrahydrate or monohydrate. If bleach activators such as tetraacetylethylenediamine are also used, they are preferably used in granulated form, cellulose ethers and starch ethers having proven useful as granulation aids, especially since they also act as release agents against the per compound. Likewise, enzymes and foam inhibitors come preferably in granulated or. coated form to be used in order to avoid an activity-reducing interaction with the other tablet components.

Furthermore, tablet auxiliaries can be admixed which improve the tablettability or. prevent the sticking of powder residues on the pressing tools, increase the breaking strength and / or promote the disintegration of the tablet in cold water and the dispersion and dissolution of the tablet ingredients. Suitable auxiliaries include depolymerized starch, starch ether, sodium sulfate, sodium chloride and in particular sodium acetate and trisodium citrate. The latter two salts are preferably used in the form containing water of crystallization. The proportion of tablet auxiliaries can be up to 15% by weight, preferably 0.5 to 5% by weight. They are preferably used as fine-grained powders with an average grain size of less than 0.5 mm, in particular less than 0.2 mm.

Tableting can be carried out in conventional tablet presses. In order to prevent powder constituents from baking on, the press rams and dies can be coated in a suitable manner, for example with Teflon. Conventional procedures, such as lifting the embossing stamp from the tablet surface with a rotational movement, can also be used. The compression ratio should be between 1: 1, 2 and 1: 2, 5, preferably 1: 1, 3 and 1: 1, 6 in order to achieve sufficient strength. The pressures are between 200 and 1200

2 2 kg / cm, preferably 300 and 1000 kg / cm. The dimensions of the

Tablets can be arbitrary in themselves. For use in household washing machines equipped with conventional detergent dispensers, however, ratios of tabletop height to tablet diameter of 1: 1 to 1: 2, preferably of 1: 1, 2 to 1: 1, 8 with a diameter of 4 have been found up to 8 cm, preferably from 5 to 7 cm, particularly proven.

The following are examples of suitable compositions (data in% by weight, based on the total amount in the tablet). Other tablet components are listed under C, which can be added as further components.

B e i s p i e l e

Components B C

The total amount of ingredients (a) to (c) is preferably 10 to 20% by weight, that of zeolite (d) preferably 20 to 35% by weight, that of sodium sulfate (g) preferably 0 to 20% by weight .-%, the cellulose ether (h) preferably 0.5 to 2% by weight, the polycarboxylate preferably 1.5 to 5% by weight and the water 1 to 5% by weight. Finally, individual powder components can also be colored.

example

The powder component (A) was prepared in such a way that a heated paste of dodecylbenzenesulfonic acid (linear C ₁ -. Alkyl residues) was neutralized with 50% NaOH in a mixer. Then, under granulating conditions, further solids and an aqueous dispersion of zeolite stabilized with 5-fold ethoxylated tallow alcohol were used. After drying with heated air, granules of the following composition were obtained:

Parts by weight of alkylbenzenesulfonate 7.3

Na tallow soap 1, 5

Zeolite NaA 21, 2nd

Talga alcohol + 5 EO 0, 5

Na carbonate 6, 6

Na sulfate 5.0

Na silicate (1: 3, 3) 3, 0

Polymeric carboxylate 3,0

Na carboxymethyl cellulose 0.7

Moisture 1, 8

The granules had a bulk density of 720 g / l and an average grain size of 0.5 mm. The polymeric carboxylate consisted of the sodium salt of a copolymer of 70 wt .-% acrylic acid and 30 wt. -% maleic acid. The powder component (B) was produced by spray drying an aqueous slurry containing zeolite (from an aqueous dispersion, stabilized with 5-fold ethoxylated tallow alcohol) and polymeric carboxylate. 4 mixture of 3-fold ethoxylated Cocosalkohol and 5 times ethoxylated ^'tallow alcohol with suspended therein op¬ tables brighteners and Parfümol sprayed: a 1 was applied to the porous, spray-dried grains. The grains had ^'then the following composition:

Parts by weight of zeolite (22% bound water) 9.0

Tallow alcohol + 5 EO 0.2

Polymeric carboxylate 1.2 nonionic surfactant mixture 4.2 optical brightener 0.1

Perfume 0.2

Moisture 0.4

The powder component had a bulk density of 680 g / l and an average grain size of 0.4 mm.

The following powder components were mixed together:

Parts by weight

Powder component A 50.6

Powder component B 15.3

Defoamer granules 0.8

Enzyme granules 1.5

Sodium perborate tetrahydrate 24.7

TAED granules 2.1

Sodium acetate trihydrate 5.0

The defoamer granules consisted of a polysiloxane, granulated with sodium sulfate as the carrier material and carboxymethyl cellulose as the granulating aid (silicone content 10%). The TAED granules consisted of 94% tetraacetylethylene diamine, granulated with 5% carboxymethyl cellulose (balance water). These granules and the enzyme granules were stained with a green dye.

The powder mixture was compressed into tablets in a tablet press (type Exakt 31), tablets with a diameter of 51 mm and a height of 35 mm being obtained from in each case 85 g of mixture. The tablets obtained had a breaking strength of 5 kg (lowest load in kg at which the tablets bridged). With open storage (20 to 25 ° C, 50% to 80% relative humidity), there was no change in tablet dimensions and no decrease in breaking strength within 2 months. Only the weight of the tablets increased slightly, i.e. H. by 2 to 3%.

The tablets dissolved in normal household washing machines during the programmed washing-in period without residue.

If the components of component (A) contained in the powder component (B) were admixed during the granulation process and the granules obtained were processed into tablets in the same way, between 15 and 30% by weight remained after the end of the washing-in period. % of the tablet undissolved in the induction device.

Claims

Patent claims

1. A process for the preparation of reduced-phosphate, finely divided zeolites, skeletal salts, anionic surfactants and nonionic surfactants from the class of detergents in tablet form containing polyglycol ether derivatives, characterized in that at least two previously prepared powdery to granular components (A) and (B) are mixed and this mixture is pressed, the components

(A) the total amount of anionic surfactants,

(B) 75 to 100% by weight of the total amount of the nonionic surfactants.

2. The method according to claim 1, characterized in that the weight ratio of anionic surfactant to non-ionic surfactant in component (A) does not fall below a ratio of 10: 1.

3. The method according to claim 1 and 2, characterized in that one starts from phosphate-free mixtures.

4. Process according to Claims 1 to 3, characterized in that the anionic surfactants are used in an amount of 3 to 20% by weight, preferably 5 to 15% by weight, based on the total weight of the tablet.

5. The method according to claim 3, characterized in that one uses up to 10 wt .-%, preferably 0.5 to 5 wt .-% of soap.

6. The method according to one or more of claims 1 to 5, characterized in that the nonionic surfactants in an amount of 3 to 15 wt .-%, preferably 4 to 10 % By weight, based on the total weight of the tablet.

7. The method according to one or more of claims 1 to 6, characterized in that further powder components are added which improve the properties of the tablet or the washing and bleaching activity of the wash liquor thus produced.

8. Detergent tablet containing fine-particle zeolites low-phosphate to phosphate-free skeletal salts, anionic surfactants and nonionic surfactants from the class of polyglycol ethers, characterized in that the tablet consists of an intimate mixture of at least two powdery to granular powder components (A) and (B ) is composed, the components

(A) the total amount of anionic surfactants,

(B) 75 to 100% by weight of the total amount of the nonionic surfactants.