EP0295525A2 - Mechanical washing process - Google Patents

Abstract

The invention relates to a machine washing process with process-controlled dosing of detergent and water amount using a pasty, phosphate-reduced to phosphate-free detergent which is essentially free of water, organic solvents and hydrotropic compounds. The paste consists of a liquid phase in the temperature range below 10 ° C, which is formed from nonionic surfactants from the class of the polyglycol ether compound, and a solid phase dispersed therein, in which the particles have an average particle size of 5 to 40 microns and at most 5% of the Particles have a grain size of up to 80 microns, the solid phase being formed from washing alkalis, sequestering compounds and other detergent constituents and, if appropriate, anionic surfactants. Process-controlled, the paste is removed from a storage container, fed to a mixing device and diluted there with water at least to such an extent that the formation of a gel phase is skipped. The aqueous mixture is fed to the washing machine and - if this has not already been done in the mixing device - diluted with further water to a concentration of up to 0.5 to 10 g / l, whereupon the washing process is started.

Description

The present invention relates to a washing process which is particularly suitable for carrying out in commercial laundries and is based on the new development of a pasty detergent which is fed into the washing process by means of a metering system which has been specifically matched to this agent.

Liquid to pasty detergents are known in large numbers. These are generally tailored to household needs. H. they should be sufficiently liquid and easy to pour and dose. Since they should also be stable in storage within a relatively wide temperature range, the use of organic solvents and / or hydrotropic additives is usually not possible. However, these additives are washing-inactive, comparatively complex and additionally require packaging volume or transport and storage capacity. In particular, a content of flammable solvents is a problem, which requires additional safety precautions due to the comparatively high throughput of detergents in laundry companies. Detergent concentrates of the type mentioned are therefore not or only of limited use for laundries.

Powder detergents are therefore mainly used in laundry companies. Since the precise dosing of such agents is problematic or labor-intensive, particularly in large companies with extensive automation, the agents are usually stored in pre-dissolved form as master liquors and metered, that is, an aqueous concentrate is prepared, which is then fed to the individual consumption points. However, the detergents usually used in laundry companies contain comparatively high proportions of washing alkalis, which are only soluble in cold water to a limited extent and moreover lead to salting-out effects. They cause phase separation, with the result that the organic components, in particular the nonionic surfactants and soaps, separate and cream. It is therefore necessary to work in a relatively strong aqueous dilution and to mix the stock liquors continuously and intensively in order to prevent the separation of individual components in the supply lines to the consumption points. Such processes therefore require high investments for spacious batch containers and the associated statics as well as for mixers and conveyors as well as a constant supply of energy for tempering and pumping around the stock liquors.

There is therefore a considerable need for detergent compositions and coordinated metering devices with which the above problems are avoided and which meet the following requirements:
- high washing power
- No washing-active additives that only serve to condition the detergent
- low need for packaging, transport and storage volume
- Easy processing even at low temperatures or from supercooled pastes
- Easy connection to the dosing system while avoiding bulk loss
- Easy and space-saving to install dosing system
- Suitability of the dosing system for fully automatic process control
- Extensive variability in the choice of the amount of detergent and the concentration of detergent
- Security against malfunctions due to phase formation and deposits in the tanks and pipes
- low energy consumption.

These problems are solved with the present invention.

• a) eines pastenförmigen, phosphatreduzierten bis phosphatfreien Waschmittels, das von Wasser, organischen Lösungsmitteln und hydrotropen Verbindungen im wesentlichen frei ist, bestehend aus einer im Temperaturbereich unterhalb 10 °C flüssigen Phase, die aus nichtionischen Tensiden aus der Klasse der Polyglycoletherverbindung gebildet wird, sowie einer darin dispergierten festen Phase, in der die Teilchen eine mittlere Korngröße von 5 bis 40 µm und höchstens 5 % der Teilchen eine Korngröße bis zu 80 µm aufweisen, wobei die feste Phase aus Waschalkalien, sequestrierend wirkenden Verbindungen und sonstigen Waschmittelbestandteilen sowie gegebenenfalls anionischen Tensiden gebildet wird, ferner
• b) einer prozeßgesteuerten Vorrichtung zum Dosieren des Wasch­mittels in den Laugenbehälter der Waschmaschine, wobei mit dieser Vorrichtung das Waschmittel einem Vorratsbehälter ent­nommen und einer Mischvorrichtung zugeführt wird, in der es mit Wasser mindestens soweit verdünnt wird, daß die Bildung einer Gel-Phase übersprungen wird, worauf das wäßrige Ge­misch, gegebenenfalls nach Zwischenschaltung von Ausgleichs­ bzw. Vorratsbehältern, der Waschmaschine zugeführt und - soweit dies nicht bereits in der Mischvorrichtung geschehen - mit weiterem Wasser auf eine Konzentration bis 0,5 bis 10 g/l verdünnt wird.

The invention relates to a machine washing process with process-controlled dosing of detergent and water, characterized by the use

• a) a paste-like, phosphate-reduced to phosphate-free detergent which is essentially free of water, organic solvents and hydrotropic compounds, consisting of a liquid phase in the temperature range below 10 ° C, which is formed from nonionic surfactants from the class of the polyglycol ether compound, and one solid phase dispersed therein, in which the particles have an average particle size of 5 to 40 μm and at most 5% of the particles have a particle size of up to 80 μm, the solid phase being formed from washing alkalis, compounds having a sequestering action and other detergent constituents and optionally anionic surfactants , further
• b) a process-controlled device for dosing the detergent into the tub of the washing machine, with this device the detergent being removed from a storage container and fed to a mixing device in which it is diluted with water at least to such an extent that the formation of a gel phase is skipped, whereupon the aqueous mixture, optionally after interposition of compensation or storage containers, fed to the washing machine and - if this has not already been done in the mixing device - diluted with further water to a concentration of up to 0.5 to 10 g / l.

There now follows a description of the individual features of the inventions.

A) Detergent

The detergent consists of a paste that is essentially free of water and organic solvents. "Substantially free of water" is understood to mean a state in which the content of liquid water, that is to say not in the form of water of hydration and constitutional water, is below 2% by weight, preferably below 1% by weight and in particular below 0 , 5% by weight. Higher water contents are disadvantageous because they increase the viscosity of the agent disproportionately and reduce the stability. Organic solvents, which include the low molecular weight and low-boiling alcohols and ether alcohols commonly used in liquid concentrates, as well as hydrotropic compounds, are also absent, apart from traces that can be introduced with individual active ingredients.

The detergent consists of a liquid phase and a finely divided phase dispersed therein.

The liquid phase consists essentially of nonionic surfactants or surfactant mixtures melting at temperatures below 10 ° C. It is advisable to use surfactants or their mixtures whose pour point (solidification point) is below 5 ° C, so that solidification of the paste at lower transport and storage temperatures is avoided.

Examples of such surfactants are e.g. B. alkoxylated alcohols, which can be linear or methyl-branched in the 2-position (oxo alcohols), and have 9 to 16 carbon atoms and 2 to 10 ethylene glycol ether groups (EO). Alkoxylates which have both EO groups and propylene glycol ether groups (PO) are also suitable because of their low pour point. Examples of suitable nonionic surfactants are:
C₉₋₁₁ oxo alcohol with 2 to 10 EO, such as C₉₋₁₁ + 3 EO, C₉₋₁₁ + 5 EO, C₉₋₁₁ + 7 EO, C₉₋₁₁ + 9 EO;
C₁₁₋₁₃ oxo alcohol with 2 to 8 EO, such as C₁₁₋₁₃ + 2 EO, C₁₁₋₁₃ + 5 EO, C₁₁₋₁₃ + 6 EO, C₁₁₋₁₃ + 7 EO;
C₁₂₋₁₅ oxo alcohol + 3 - 6 EO, such as C₁₂₋₁₅ + 3 EO, C₁₂₋₁₅ + 5 EO;
Isotridecanol with 3 to 8 EO;
linear fatty alcohols with 10 to 14 carbon atoms and 2.5 to 5 EO; linear or branched C₉₋₁₄ alcohols with 3 to 8 EO and 1 to 3 PO, such as C₉₋₁₁-oxo alcohol + (EO) ₄ (PO) ₁₋₂ (EO) ₄ or - C₁₁₋₁₃-oxo alcohol + ( EO) ₃₋₁₀ (PO) ₁₋₅ with randomly distributed alkoxyl groups;
linear saturated and unsaturated C₁₂₋₁₈ fatty alcohols or C₉₋₁₅ oxo alcohols with 1 to 3 PO and 4 to 8 EO, such as C₁₂₋₁₈ coconut alcohol + (PO) ₁₋₂ (EO) ₄₋₇, oleyl alcohol or 1 : 1-mixture of cetyl oleyl alcohol + (PO) ₁₋₂ (EO) ₅₋₇, C₁₁₋₁₅ oxo alcohol + (PO) ₁₋₂ (EO) ₄₋₆.

Also ethoxylated alcohols whose terminal hydroxyl groups are alkylated by lower alkyl groups are suitable due to their low pour point within the scope of the invention, for example a C₁₀₋₁₄ alcohol having 3 to 10 EO groups and a terminal methoxyl group. Other suitable nonionic surfactants are EO-PO-EO block polymers with a correspondingly low pour point and ethoxylated alkylphenols, such as nonylphenol with 7 to 10 EO. The latter surfactants can, however, because of their reduced biodegradability in certain areas may be excluded from use. They are therefore less preferred.

The content of the pastes in the nonionic surfactants mentioned should be such that, on the one hand, they are still sufficiently free-flowing and pumpable, but on the other hand they are not so fluid that there is a risk of segregation. Pastes with a content of 15 to 30% by weight, preferably 18 to 28% by weight and in particular 20 to 25% by weight, of liquid nonionic surfactants with a low pour point (below 5 ° C.) are suitable. If surfactants with a higher pour point, for example that of 5 to 20 ° C., are used in a mixture with particularly low-melting surfactants, the minimum content is somewhat higher, for example in the range from 18% by weight, preferably from 22 to 24% by weight. , the maximum content being 35% by weight, preferably 30% by weight.

In individual cases, a single nonionic surfactant can already have the desired requirements with regard to low pour point, favorable flow behavior, high detergency and low foaming. An example of this are oleyl alcohol or mixtures rich in oleyl alcohol, which was first reacted with 1 to 2 PO and then with 5 to 7 EO. However, particularly favorable properties are often achieved with mixtures of nonionic surfactants with different degrees of ethoxylation and possibly different C chain lengths. Mixtures of nonionic surfactants with a low degree of ethoxylation and low pour point, for example C₉₋₁₅ alcohols with 2 to 5 EO, and those with a higher degree of ethoxylation and higher pour point, for example C₁₁₋₁₅ alcohols with 5 to 7 EO, are therefore particularly preferred. The mixing ratio between the two alcohol ethoxylates depends both on the washing requirements and the flow behavior of the washing paste and is generally between 15: 1 to 1: 3, preferably 8: 1 to 1: 1. Examples of this are a mixture of 2 parts by weight of C₉₋₁₁ -Oxo alcohol + 2.5 EO and 1 part by weight of C₁₁₋₁₃-oxo alcohol + 7 EO or a mixture of 3 parts by weight of a C₁₁₋₁₋-oxo alcohol + 3 EO and 2 parts by weight of a C₉₋₁₃-oxo alcohol + 8 EO and a mixture of 7 parts by weight of C₁₃-oxo alcohol + 3 EO and 1 part by weight of the same alcohol + 6 EO.

Finally, the flow properties of the pastes can be modified by adding low molecular weight polyethylene glycols (e.g. 200 to 800). The addition can be up to 15% by weight, for example. However, the contribution of these additives, which are often also included in the nonionic surfactants, to the detergency is comparatively low. However, they can have a foam-suppressing effect and are therefore desirable. Their proportion is preferably up to 10% by weight, in particular 0.5 to 8% by weight.

The polyglycols can also be wholly or partly replaced by paraffin oils or liquid paraffin mixtures, which do not contribute to the washing power, but make the paste easier to process, especially during the grinding of the ingredients, and bring about a considerable reduction in foam, which is particularly noticeable in the rinse cycle makes. The proportion of such paraffin oils or paraffin oil mixtures is expediently not more than 8% by weight, preferably not more than 6% by weight. Liquid long-chain ethers can also be used in the same amount for the same purpose. Examples include the C₈₋₁₆ alkyl ethers of dicyclopentenol.

The detergent contains a solid phase which is homogeneously dispersed in the liquid phase and contains the other detergent constituents which have a cleaning action and, if appropriate, auxiliaries. These other detergent components which have a cleaning action primarily include washing alkalis and sequestering compounds. Anionic surfactants, in particular those from the class of the sulfonate surfactants and the soaps, can also be present.

The preferred washing alkali is sodium metasilicate of the composition Na₂O: SiO₂ = 1: 0.8-1: 1.3, preferably 1: 1, which is used in anhydrous form. In addition to the metasilicate, anhydrous soda is also suitable, but because of absorption processes it requires larger proportions of the liquid phase and is therefore less preferred. The proportion of the agents in metasilicate can be 35 to 70% by weight, preferably 40 to 65% by weight and in particular 45 to 55% by weight, and in soda 0 to 20% by weight, preferably 0 to 10% by weight. -%.

Suitable sequestrants are those from the class of aminopolycarboxylic acids and polyphosphonic acids. The aminopolycarboxylic acids include nitrilotriacetic acid, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid and their higher homologues. Suitable polyphosphonic acids are 1-hydroxyethane-1,1-diphosphonic acid, aminotri- (methylenephosphonic acid), ethylenediaminetetra- (methylenephosphonic acid) and their higher homologs, such as. B. Diethylenetraminetetra (methylenephosphonic acid). The aforementioned polycarboxylic acids or polyphosphonic acids are usually used in the form of the sodium or potassium salts. Sodium nitrilotriacetate is preferably used in proportions of up to 10% by weight, preferably 2 to 6% by weight.

Suitable sequestering agents are also polycarboxylic acids or hydroxypolycarboxylic acids in the form of the alkali metal salts, for example sodium citrate and sodium gluconate.

The preferred sequestering agents include homopolymeric and / or copolymeric carboxylic acids or their sodium or potassium salts, with the sodium salts being preferred. Suitable homopolymers are polyacrylic acid, polymethacrylic acid and polymaleic acid. Suitable copolymers are those of acrylic acid with methacrylic acid or copolymers of acrylic acid, methacrylic acid or maleic acid with vinyl ethers, such as vinyl methyl ether or vinyl ethyl ether, furthermore with vinyl esters, such as vinyl acetate or vinyl propionate, acrylamide, methacrylamide and with ethylene, propylene or styrene. In those 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 70 mole percent, preferably less than 60 mole percent. Copolymers of acrylic acid or methacrylic acid with maleic acid have proven to be particularly suitable, as are characterized, for example, in EP 25 551-B1. These are copolymers which contain 50 to 90% by weight of acrylic acid or methacrylic acid and 50 to 10% by weight of maleic acid. Copolymers in which 60 to 85% by weight of acrylic acid and 40 to 15% by weight of maleic acid are present are particularly preferred.

Also useful are polyacetal carboxylic acids, such as those described in U.S. Patents 4,144,226 and 4,146,495, which are obtained by polymerizing esters of glycolic acid, introducing stable terminal end groups, and saponifying to the sodium or potassium salts. Also suitable are polymeric acids which are obtained by polymerizing acrolein and disproportionating the polymer according to Canizzaro using strong alkalis. They are essentially made up of acrylic acid units and vinyl alcohol units or acrolein units.

The molecular weight of the homo- or copolymers is generally 500 to 120,000, preferably 1,500 to 100,000.

The proportion of the agents in polyacids or polymer acids containing carboxyl groups is 0 to 10% by weight, preferably 1 to 7.5% by weight and in particular 2 to 5% by weight, and that of polyphosphonic acids 0 to 3% by weight. , preferably 0.05 to 1.5% by weight and in particular 0.1 to 1% by weight. They are used in an anhydrous form.

The washing pastes are preferably phosphate-free. If a phosphate content is ecologically harmless (for example in the case of wastewater treatment that eliminates phosphates), polymeric phosphates, such as sodium tripolyphosphate (STP), can also be present. Their proportion can be up to 20% by weight, based on the agent, the proportion of the other solids, e.g. B. the sodium silicate, is reduced accordingly. The proportion of the STP is preferably at most 15% by weight and in particular at most 10% by weight.

Fine-particle zeolites of the NaA type which have a calcium binding capacity in the range from 100 to 200 mg CaO / g (according to the information in DE 12 24 837) are also to be regarded as sequestering agents in the sense of the present invention. Their particle size is usually in the range of 1-10 µm. They are used in dry form. The water contained in bound form in the zeolites does not interfere in the present case. The zeolite content is 0 to 20% by weight, preferably 0 to 10% by weight.

Anionic surfactants are suitable as further cleaning additives which can be incorporated into the detergent in a solid, finely divided, largely anhydrous form. Sulfonates and fatty acid soaps, which are preferably present as sodium salts, have proven to be particularly suitable. Suitable are alkylbenzenesulfonates with linear C₉₋₁₃ alkyl chains, especially dodecylbenzenesulfonate, linear alkanesulfonates with 11 to 15 carbon atoms, as can be obtained by sulfochlorination or sulfoxidation of alkanes and subsequent saponification or neutralization, alphasulfofatty acid salts and their esters, which derived from saturated C₁₂₋₁₈ fatty acids and lower alcohols such as methanol, ethanol and propanol, and olefin sulfonates such as those used for. B. by SO₃-sulfonation final C₁₂₋₁₈ olefins and subsequent Akalic hydrolysis. Preferred surfactants are alkylbenzenesulfonates. Suitable soaps are those of saturated and / or unsaturated C₁₂₋₁₈ fatty acids, for example soaps obtained from coconut, palm kernel or tallow fatty acids. In the interest of a low foaming rate when using the compositions, the proportion of the sulfonate surfactants should not exceed 4% by weight, based on the composition. It is preferably 0.5 to 2.5% by weight of sodium dodecylbenzenesulfonate. An addition of sulfonate surfactant not only increases the washing power, but also improves the stability of the pastes against signs of sedimentation and facilitates the dispersion of the paste in the water. Surprisingly, it has also been found that the sulfonate surfactant essentially distributes itself in the liquid phase and improves the solid / liquid balance in favor of the liquid phase. Pastes containing sulfonate surfactants can therefore absorb larger amounts of solids, or the proportion of nonionic surfactant can be reduced accordingly without any appreciable increase in viscosity.

An addition of soap, which can be up to 1% by weight, preferably up to 0.5% by weight and in particular 0.1 to 0.3% by weight, based on the composition, likewise increases the suspension stability of the paste . Such an addition also reduces the tendency to foam and improves the washing power of the compositions. Larger proportions than 1 to 2% by weight can solidify the paste and should therefore be avoided.

Washing aids can be considered as further constituents, which are also predominantly assigned to the solid phase. These include graying inhibitors, optical brighteners, foam inhibitors, bleaches and dyes. Insofar as fragrances are used which are generally liquid, these pass into the liquid phase. Because of their small amount, however, they have no appreciable influence on the flow behavior of the pastes.

Suitable graying inhibitors are cellulose ethers, such as carboxymethyl cellulose, methyl cellulose, hydroxyalkyl celluloses and mixed ethers, such as methyl hydroxyethyl cellulose, methyl hydroxypropyl cellulose and methyl carboxymethyl cellulose. Na carboxymethyl cellulose and mixtures thereof with methyl cellulose are preferably used. The proportion of graying inhibitors is generally 0.2 to 2% by weight, preferably 0.5 to 1.5% by weight.

In particular, derivatives of diaminostilbenedisulfonic acid or its alkali metal salts are included as optical brighteners for textiles made from cellulose fibers (cotton). Are suitable for. B. salts of 4,4'-bis (2-anilino-4-morpholino-1,3,5-triazin-6-yl-amino) -stilbene-2,2'-disulfonic acid or compounds of the same structure, which instead of Morpholino group carry a diethanolamino group, a methylamino group or a 2-methoxyethylamino group. Brighteners can also be used of the substituted 4,4'-distyryl-diphenyl type; e.g. B. the compound 4,4'-bis (4-chloro-3-sulfostyryl) diphenyl. Mixtures of brighteners can also be used. Brighteners of the 1,3-diaryl-2-pyrazoline type are suitable for polyamide fibers, for example the compound 1- (p-sulfamoylphenyl) -3- (p-chlorophenyl) -2-pyrazoline and compounds of the same structure. The content of optical brighteners or brightener mixtures in the agent is generally 0.01 to 1% by weight, preferably 0.05 to 0.5% by weight.

Known polysiloxane-silica mixtures are suitable as foam inhibitors, the fine-particle silica contained therein preferably being silanated. The polysiloxanes can consist both of linear compounds and of crosslinked polysiloxane resins and of their mixtures. Other suitable defoamers are paraffin hydrocarbons, including the paraffin oils already mentioned, but also microparaffins and paraffin waxes, whose melting point is above 40 ° C. Usable defoamers are also saturated fatty acids or soaps with 18 to 24, preferably 20 to 22 carbon atoms, for. B. sodium behenate. The proportion of additional, i.e. H. Foam inhibitors beyond the paraffin oil can be up to 2% by weight, preferably up to 1% by weight, correspondingly less in the case of soaps. In many cases, however, a suitable selection of the nonionic surfactants can reduce the tendency to foam, so that the use of defoamers can be dispensed with.

Bleaching agents can also be present as a further component of the solid phase. Per compounds such as sodium perborate monohydrate, caroates (KHSO₅) and organic peracids such as perbenzoates or peroxyphthalates can be used. These per-compounds are in the claimed means due to the extensive absence of water is stable on storage. If appropriate, known bleach activators can also be present, which hydrolyze with the per compounds to form peracids when water is added, for example tetraacetylethylene diamine or phthalic anhydride. However, since in commercial laundries the bleaching component is usually added directly to the wash liquor and is generally used only when there is a particular need, it is usually possible to dispense with bleaching agents in the paste.

The constituents contained in the solid phase should be finely divided and have an average grain size of 5 to 40 μm, with at most 5% of the particles having a grain size of at most 80 μm. The average grain size is preferably 10 to 30 μm and in particular 10 to 20 μm, the maximum grain size being below 50 μm, in particular below 40 μm. The average particle size relates to the volume distribution, which is determined by known methods (e.g. Coulter Counter).

The viscosity of the pastes is in the range from 20 Pa.s to 1,000 Pa.s (Pascal. Sec), measured at 20 ° C according to Brookfield 6/10 (spindle no. 6 at 10 revolutions per minute). The preferred viscosity range is 30 to 300 Pa.s, in particular 50 to 150 Pa.s. The pastes are usually thixotropic. At room temperature, their viscosity is so high without the use of shear forces that under the exclusive influence of gravity they do not flow out of the storage container or a measuring cup or in a reasonable time. In this respect, they differ fundamentally from known water-free, pourable liquid concentrates, for example those according to EP 30096, in which the proportion of liquid nonionic surfactants or organic solvents is significantly higher.

For the production of the pasty detergents, the liquid constituents, which are expediently heated to temperatures of 40 ° C. to 60 ° C., are premixed with the solids already in powder form. The premix is then ground in a grinding device, for example a colloid mill, to the particle size specified for the solid phase and homogenized, excessive heating of the product being avoided by suitable cooling of the device. If necessary, the homogenized paste is degassed under vacuum in a ventilation system. Thereafter, thermally sensitive recipe components such as fragrances, dyes, organic per-compounds, layered silicates and soaps can be added to serve as the final viscosity adjustment. The finished paste can be filled directly into the packaging container.

B) dosing device

The dosing device essentially consists of the following basic elements (Figure 1):
- a storage container (1) for the washing paste (2),
- a removal and conveying device (3) for the paste,
- A mixing device (4) for the paste with water, which is removed from a feed (5),
a feeder (6) equipped with metering valves, which is possibly connected to an intermediate container or expansion tank (7), to the point of consumption (washing machine) (8),
- A control device (9) that registers the need for detergent or wash liquor at the point of use and the functions of the devices (3), (4) and (5) including the metering of the water supply from (6) or the removal from (7 ) controls depending on the need. The Control lines are drawn in dashed lines and the main pulse directions are marked by arrows.

The storage container (1) is expediently identical to the shipping container in which the product (A) is delivered. Its shape can be any. Examples of this are barrels, barrels or cartridges made of metal or plastic material or also foil packaging, for example sacks or bags, which can be packed in outer cartons. Containers with rigid outer walls and a circular or square cross section are preferred, since these facilitate the removal of the paste.

The removal device is intended to ensure that the storage container is emptied as completely as possible and its function and design are adapted to the function of the storage container and the mixing device. It can consist of a simple pipeline that connects the storage container to the mixing device. However, it can also contain additional elements that take over and regulate product management. Figure II to VI illustrate some embodiments, without the invention being limited thereto.

Figure II shows an arrangement in which the paste is removed from an open container. The extraction line (31) extends to the bottom of the container. The mixing device (4), which can consist of an injector and generates a negative pressure in the extraction line, sucks in the paste and mixes it with water, which is supplied via the line system (5). The mixing device (4) can also consist of a motor-driven pump which draws in the paste via line (3) and mixes it with the inflowing water on the pressure side, for example by means of a nozzle.

Figure III shows an arrangement in which the container is equipped with a movable, tightly closing plate (follower plate 21). Due to its weight, this follower plate exerts an additional pressure on the surface of the paste and causes an even lowering of the paste surface, stripping of paste residues from the inner wall of the container and partial liquefaction and easier conveyance of the thixotropic paste. In this case, the product can be removed from the underside of the follower plate. The follower plate can also be driven by a motor or by means of a pressure ram, its propulsion being regulated by the control device. In this way, the material can be pressed into the extraction line (31) and conveyed to the mixing device.

Figure IV shows an arrangement in which the mixing device (4) dips into the storage container and removes the paste directly from it.

Figure V shows arrangements in which the paste is conveyed under pressure. This pressure can act, for example, hydraulically or pneumatically on a membrane, a flexible inner container (bag), a piston or a hydraulic cylinder. The piston can be fed, for example, by means of a rack, threaded spindle or eccentric shaft. Such a device and the arrangement with a hydraulic cylinder also allow a controlled feed and thus an exact dosage of the paste at this point.

Figure VI shows arrangements with descending product guidance. In the arrangement on the left, the storage container consists of a cartridge, which is closed at the top by a movable plate. This plate can weighed down or be equipped with a printing device according to FIG. The right arrangement shows a container in which the paste is filled into a plastic inner bag. The bag shrinks as the emptying progresses, the evenness of the emptying also being facilitated by a follower plate which can be pressurized or equipped with controlled propulsion. Such an arrangement is suitable for a cardboard packaging with an inner bag as a storage container. The paste can be conveyed to the mixing device (4) either by a feed pump (3) or by the pressure exerted on the paste (compare arrangements according to Figure (V) or by the negative pressure exerted by the mixing device (4) or by a suitable combination The conveying by means of negative pressure is possible, for example, in an arrangement in which the mixing device (4) consists of an injector which works on the principle of the water jet pump. In this case, the mixing ratio is controlled by means of suitable throttle devices or Dosing valves which are arranged in the water inlet (5) or the removal line (31), but the mixing device (4) can also consist of a motor-driven propeller mixer or an equivalent mechanical mixer. In this case the paste is dosed via Arrangements with controlled paste guidance, for example with a feed pump or an Ano Rdnung according to Figure V or VI and controlled water supply via the pipe system (5).

It has proven to be expedient to integrate an additional shut-off device into the mixing device, in particular if it consists of an injector operating on the principle of the water jet pump. This shut-off device is intended to prevent the feed water from coming into contact with the supplied paste during the rest phases. Because it has demonstrated that during longer periods of rest the paste in the feed reacts with the water remaining in the injector. This can lead to the formation of crust-like deposits in the contact area, which impair the functionality of the injector. Comparable faults can occur if a high back pressure builds up briefly in long metering lines to the consumption points. This back pressure leads to the fact that supplied water is pressed into the paste suction line and possibly up to the area of the storage container. The paste can solidify to such an extent that it can no longer be conveyed.

A controllable or automatically closing shut-off device integrated in the mixing device or in the injector avoids these possible disadvantages. This shut-off device can e.g. consist of a ball shut-off valve that interrupts the access of the water to the paste feed as soon as the system is in the idle phase or a back pressure builds up inside the injector. The valve releases the feed as soon as a sufficiently large negative pressure has built up in the area of the paste feed. The valve can be controlled by means of counter pressure from an adjustable spring. The valve is preferably also opened and closed via the control device (9). In this case the locking device can e.g. consist of a rotatable shut-off valve, which is driven by a motor and whose position is based on the prevailing pressure conditions.

Figure VII illustrates an embodiment. The water enters the injector (41) under increased pressure via the inlet connection (42), passes through the cross-sectional constriction (43) and leaves the injector via the enlarged one Outlet nozzle (44). The rotatable shut-off device (45), which is shown in the drawing in the open position, is arranged laterally in the area of the cross-sectional expansion in which a negative pressure is formed. The opening is closed by a rotation of 90 °, thus preventing the water from entering the paste suction nozzle (46).

A further embodiment of the mixing device, with which the feed water can effectively be prevented from penetrating into the paste feed, is illustrated by FIG. VIII. The paste feed (31) coming from the feed pump (3) and the water feed line (5) open into a vertically upright, open-ended funnel (32), the outlet of which leads to the mixing device (4). The water supply can be designed by installing nozzles or by a corresponding, for example tangential arrangement of the outflow opening in such a way that the paste and water are premixed and the paste is prevented from adhering to the funnel wall. The function of the funnel can be monitored and, for example, the feed can be interrupted by installing sensors which register the filling level of the funnel if the further conveyance is delayed or interrupted by backflow or malfunctions of the mixing device. An overflow device can also act in the same sense, which absorbs the overflowing portions of paste and feed water and, after eliminating the fault, forwards their contents to the mixing device.

The paste is diluted in the mixing device at least to such an extent that the gel phase is skipped. In the area of this gel phase, the nonionic surfactants and the salts which are not or only partially dissolved form a highly viscous, viscous gel which is poorly or relatively slowly distributed and dissolved in water. Therefore, the paste in the mixing device a sufficient amount of water is added so that this intermediate phase cannot form. In general, 0.5 times to 1.5 times the amount of water is sufficient for this. Of course, the paste can also be diluted more, for example up to the concentration of the ready-to-use lye. In general, however, a lower dilution will be chosen, especially if several machines are to be operated in one cycle with one metering device. It is therefore expedient to add only enough water to form a concentrate which is easy to convey and to meter, and which is then diluted to the desired alkali concentration at the points of use, ie in the washing machines. Suitable dilution ratios of paste to water are between 2: 1 and 1:10, preferably 3: 2 and 1: 3.

A conductivity sensor can be installed after the mixing device, which registers the conductivity and thus the concentration of the detergent solution. The function of the feed and dosing system can thus be monitored effectively and its operation can be interrupted in the event of faults. This applies in particular to cases in which the paste supply is interrupted or does not occur due to the emptying of the storage container or a disturbance in the water supply occurs.

The aqueous concentrate can be fed directly to the individual washing machines via appropriate, consumption-controlled distribution devices. However, if several machines are operated simultaneously or in cycles, it may be advisable to arrange an intermediate container or expansion tank (7) between the mixing device and the point of use so that a sufficient supply of aqueous detergent concentrate is available at all times during peak operation. To prevent possible settling of components of the concentrate that are not completely dissolved, especially in stationary or to prevent break times, the expansion tank is preferably equipped with a mixing or stirring device. In addition, the line system can be designed as a ring line and the expansion tank can be included in this system. In this ring line, the concentrate is continuously pumped around in a circuit and only the required quantity is supplied or removed from it. This circulation of the concentrate effectively prevents possible settling of undissolved or crystallizing constituents or clogging of the line system or the metering valves.

An expansion tank is not necessary if the individual dosing elements, i.e. H. Tapping device, mixing device, water supply valve (5) and the metering valves (6) to the tapping points are controlled synchronously. Any pressure fluctuations in the line system can be detected by a pressure sensor and compensated for by appropriate control of the pumps and valves. If several washing machines are operated at the same time, the cycle times follow each other so briefly that undesired sedimentation does not occur.

The concentrate is fed into the washing machine via the metering valve (6), which, like the metering and mixing devices already described above, is controlled by the process computer. An optimal washing result and an optimal utilization of the detergent can be achieved by a consumption-oriented control. In this case, the electrical conductivity of the wash liquor, which is determined and monitored with a measuring cell arranged in the washing machine, has proven to be a control variable. Not only can the desired initial concentration be set precisely, but the consumption of detergent substance can also be absorbed by it Pollutants are tracked, which is generally associated with a decrease in conductivity. In the event of a large amount of dirt, washing-active concentrate can then be replenished automatically. On the other hand, when washing only little soiled laundry, for example hotel bed linen used only once, washing concentrate can be saved and unnecessary additional consumption can be avoided by the consumption-oriented dosage.
Instead of the conductivity measurement, other methods can also be used, for example a nephelometric control of the wash liquor.

The concentration of the wash liquor is in the range of 0.5 to 10 g / l. It is based on the degree of soiling of the laundry, ie in the case of less soiled laundry the application concentration is generally 0.5 to 5 g / l, in the case of heavily soiled laundry 5 to 10 g / l. In special cases, e.g. B. in heavily soiled work clothes, the concentration can be even higher and be, for example, 12 g / l. In general, it is 2 to 8 g / l. The liquor ratio (kg of textile to liter of wash liquor) is generally 1: 2 to 1:10, preferably 1: 4 to 1: 6. Usually, softened (permuted) water is used, and also for rinsing, at least for the first rinse cycle , usually softened water is used. Basically, the washing process in the machine does not differ significantly from the conventional working methods, with the exception that (as explained above) the detergent can be automatically replenished if there is an increased demand as a result of heavy soiling.

Examples

• 1. The detergent batch (200 kg) contained the following anhydrous components (in% by weight):
  24.0% nonionic surfactant
  2.0% Na dodecylbenzenesulfonate
  8.5% Na nitrilotriacetate
  55.0% Na metasilicate (1: 1)
  8.5% pentasodium triphosphate
  1.5% cellulose ether
  0.5% optical brightener
  As a nonionic surfactant, a mixture of saturated C₁₂₋₁₄ fatty alcohol + 3 EO and C₁₂₋₁₄ fatty alcohol + 5 EO in a weight ratio of 1: 1 with a freezing point (pour point) of 5 ° C was used.
  The mixture was milled in a milling device (colloid mill type SZEGO-1) for 30 minutes. The ground product (outlet temperature 45 ° C.) had an average grain size of 18.6 μm and a viscosity of 50 Pa.s (according to Brookfield 6/10 at 20 ° C.). 0.1% of a dye was mixed in a cooled paste mixing kettle with a wall scraper. The end product was a storage-stable, pumpable paste with a specific weight of 1.7 g / ml.
  The paste was filled into barrels (capacity 50 or 200 l), which could be connected directly to the dosing system described above. Mixing with water in a ratio of 1: 1 resulted in a viscous, easily metered and easily dilutable with water Concentrate (stock liquor with a low tendency to foam). The diluted concentrate was temporarily stored in a storage container (with level-dependent feed) and fed from there to the washing machine. The feed lines were designed as ring lines in which the concentrate was pumped in a circuit. Detergent components did not settle.
• 2. Example 1 was repeated using 57 wt .-% metasilicate and 22 wt .-% of a nonionic surfactant mixture of 2 parts by weight of C₉₋₁₁-oxo alcohol with 5 EO and 1 part by weight of C₁₂₋₁₃-oxo alcohol with 6 EO. The average grain size of the millbase was 16.5 µm, the viscosity 54 Pa.s (Brookfield 16/20 at 20 ° C). This mixture, too, was stable in storage, pumpable and meterable and, when diluted with water (1: 1 to 1: 3), gave low-viscosity, low-foaming concentrates with comparable properties.
• 3. Example 1 was repeated, replacing 0.2% by weight of the nonionic surfactant with the same amount of sodium tallow soap. The viscosity of the paste increased to 68 Pa.s. The aqueous bases had a particularly low tendency to foam.
• 4. A paste of the following composition was produced (in% by weight):
  17.5% C₁₃ oxo alcohol + 3 EO
  2.5% C₁₃ oxo alcohol + 6 EO
  2.0% Na dodecylbenzenesulfonate
  8.0% polyethylene glycol (MG 400)
  7.5% 3: 1 acrylic acid-maleic acid copolymer (MW 70,000), present as sodium salt
  2.5% ethylenediaminetetra (methylenephosphonate), Na₆ salt
  5.0% Na nitrilotriacetate
  52.5% Na metasilicate
  2.0% cellulose ether
  0.3% optical brightener
  0.2% Na tallow soap
  The abbreviation MG means molecular weight. The processing of the constituents into a homogeneous, stable paste was carried out analogously to the manner given in Example 1. The average grain size was 17.0 µm, with no portions with a grain size above 40 µm. The viscosity was 76 Pa.s (according to Brookfield 6/10) at 20 ° C. With regard to its performance properties, the paste corresponded to the agent according to Example 1 with an even lower tendency to foam, especially during the rinsing phase.
• 5. Compared to Example 4, the polyethylene glycol ether was replaced by a 1: 1 mixture of paraffin oil and a lauryl ether of dicyclopentenol. The energy required to grind the paste was about 20% less than in Example 4. The viscosity was 74 Pa.s. Furthermore, the tendency to foam of the paste diluted to the application concentration was further reduced compared to Example 4.
• 6. The batch contained the following liquid constituents (in% by weight):
  22% oleyl alcohol-cetyl alcohol (1: 1) + 1.5 PO + 6 EO
  6% polyethylene glycol 400
  The composition of the solids, including Na-dodecylbenzenesulfonate, corresponded to the information in Example 4. The paste, ground to an average grain size of 18.2 μm and having a viscosity of 82 Pa.s, was stable on storage and easy to convey. Your tendency to foam at application concentration was minimal. In addition, the detergent was characterized by improved rinsability in the rinse phase.
• 7. The pastes produced according to the above examples were filled and stored in cylindrical metal barrels (content 200 l). The paste was removed via a suction line which ended centrally in a follower plate (21) according to FIG. III. The paste was fed via a feed pump to a centrifugal pump, in which mixing with the softened water supplied via a metering valve (5) took place in a ratio of 1: 1. The feed into the washing machines (car wash with 10 units) was carried out via a central line with valve-controlled feeds to the individual machines. The control was carried out depending on the conductivity of the diluted wash liquor in the washing machines and was carried out in such a way that the extraction pump, the mixing device, the supply valve for the softened water and the respective metering valves on the individual washing machines worked in synchronism. With the help of an additional pressure sensor in the line system, this control system was checked and a constant low overpressure was maintained. This made the installation of an expansion tank unnecessary. Solid components of the diluted paste did not settle within the usual cycle times. After long periods of inactivity (e.g. overnight), the pipe system was flushed through a return pipe as a precaution. The system worked faultlessly during a 1/2 year test phase.

Claims (13)

1. Machine washing process with process-controlled dosing of detergent and water, characterized by the use a) a paste-like, phosphate-reduced to phosphate-free detergent which is essentially free of water, organic solvents and hydrotropic compounds, consisting of a liquid phase in the temperature range below 10 ° C, which is formed from nonionic surfactants from the class of the polyglycol ether compound, and one solid phase dispersed therein, in which the particles have an average particle size of 5 to 40 μm and at most 5% of the particles have a particle size of up to 80 μm, the solid phase being formed from washing alkalis, compounds having a sequestering action and other detergent constituents and optionally anionic surfactants , further b) a process-controlled device for dosing the detergent into the tub of the washing machine, with this device the detergent being removed from a storage container and fed to a mixing device in which it is diluted with water at least to such an extent that the formation of a gel phase is skipped, whereupon the aqueous mixture, optionally after interposition of equalizing or. Storage containers, fed to the washing machine and - if this is not already done in the mixing device - diluted with further water to a concentration of up to 0.5 to 10 g / l. 2. The method according to claim 1, characterized in that the content of the paste-like agent of nonionic Surfactants is 15 to 30, preferably 18 to 20 and in particular 20 to 25% by weight. 3. The method according to claims 1 and 2, characterized in that the pasty detergent contains low-melting mixtures of nonionic surfactants with different degrees of ethoxylation and optionally different C chain length. 4. Process according to claims 1 to 3, characterized in that the liquid phase of the pasty agent up to 12 wt .-% at least one compound from the class of low molecular weight polyethylene glycols, paraffin oils and liquid ethers with 8 to 16 C- Contains atoms in the hydrocarbon chain. 5. Process according to claims 1 to 4, characterized in that the pasty agent up to 4 wt .-%, preferably 0.5 to 2.5 wt .-% of a sulfonate surfactant from the class of C₁₀₋₁₃ alkylbenzenesulfonates , C₁₁₋₁₅ alkane sulfonates, C₁₂₋₁₈ alpha olefin sulfonates, alpha sulfo fatty acids and their esters and up to 1% by weight, preferably up to 0.5% by weight of a C₁₂₋₁₈ soap. 6. The method according to claims 1 to 5, characterized in that the agent contains sodium metasilicate in proportions of 35 to 70 wt .-%, preferably from 40 to 65 wt .-%. 7. Process according to claims 1 to 6, characterized in that the average grain size of the dispersed solid phase is between 10 and 30 µm, preferably 10 and 20 µm and the maximum size of the particles is less than 50 µm, preferably less than 40 µm. 8. The method according to claims 1 to 7, characterized in that the Brookfield (6/10 at 20 ° C) measured viscosity of the pasty agent used from 20 to 1,000 Pa. s, preferably from 30 to 300 Pa.s. 9. The method according to claim 1, characterized in that one uses a metering device which consists essentially of the following elements:
- a storage container (1) for the washing paste (2),
- a removal and conveying device (3) for the paste,
- A mixing device (4) for the paste with water, which is removed from a feed (5),
- A feed (6) to the point of consumption (washing machine) (8),
- A control device (9) that registers the need for detergent or wash liquor at the point of use and controls the functions of devices (3), (4) and (5) including the metering of the water supply via (6) depending on the need. 10. The method according to claim 9, characterized in that the paste in the mixing device (4) with softened water in a ratio of 2: 1 to 1:10, preferably 3: 2 to 1: 3 diluted. 11. The method according to claims 9 and 10, characterized in that the device additionally contains a surge tank (7). 12. The method according to claims 9 and 10, characterized in that the function of the elements (3), (4), (5) and (6) is controlled synchronously as a function of the conductivity of the dilute wash liquor measured in (8). 13. The method according to one or more of claims 9 to 12, characterized in that the mixing device is an injector working on the principle of the water jet pump with an integrated shut-off valve.

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