DE3300243A1 - DISHWASHER ON AQUEOUS BASE FOR AUTOMATIC DISHWASHER - Google Patents

Description

description

The invention relates to an aqueous-based dishwashing detergent for automatic dishwashers.

Commercially available detergents for common household dishwashers are in powder form and have the disadvantage that they are composed unevenly are, are relatively expensive to produce, stick together when wet and are difficult to disperse Form lumps or dust in dry form and cause allergies. Liquid dishwashing detergents In contrast, they can be used in automatic dishwashers because of the strong foam formation, the extremely low Use poor viscosity and excessively high alkalinity.

The more recent development has focused on gel-like or concentrated thixotropic mixtures, such as abrasives and dishwashing detergents in the form of thixotropic Pastes. However, these products are unsuitable as dishwashing detergents because their viscosity is too high. because they get stuck in the dispenser of the dishwasher and stain the dishes and glasses Forming deposits. Ideally, thixotropic cleaning agents should be highly viscous or have a high viscosity when not in use. are in the plastic Bingham state and have relatively high flow values. Under shear stress these products should, for example, when shaken in the container or when squeezed out through an opening

liquefy quickly and if the expended Shear force will quickly return to the highly viscous or plastic state after Bingham. Furthermore, the stability of these products with regard to phase separation or exudation of constituents is important of considerable importance when standing for a long time.

The detergents for automatic dishwashers previously in gel form with those mentioned above Properties give difficulties in particular in the case of conventional household dishwashers. It is for such detergents for automatic dishwashers Generally recommended that they use sodium tripolyphosphate (NaTPP) to soften the water or to bind the salts that give the water hardness and to emulsify and / or peptize dirt and also sodium silicate to achieve the desired alkalinity for effective cleaning and protection for the glaze and decor of porcelain, and preferably sodium carbonate to increase the alkalinity, furthermore a chlorine-releasing agent for better removal of dirt stains or water stains, and ultimately a foam suppressor / surfactant should contain · to prevent foam formation to reduce and thus to support the effectiveness of the machine cleaning process and around ultimately to give the required cleaning effect; this is for example in "SDA Detergents in Depth, Formulations Aspects of Machine Dashwashing "presented by Thomas Oberle (1974). Cleaning agents structured in this way are mostly liquids or powders. The combination of these ingredients in gel form, which is suitable for household dishwashers are suitable has led to considerable difficulties. In general, these Means the hypochlorite bleaching agent has been omitted because it contains other chemically active ingredients and in particular

ere the surfactant reacts and thereby decomposes the suspending agent or the thixotropic agent and impairs its effectiveness and so, for example, US Pat Contains silicates, phosphates, polyphosphates and small amounts of surfactant and foam suppressor, but refrain from using bleach. A similar product is known from US Pat. No. 4,147,650 which contains hypochlorite as a bleaching agent; however, this product is in the form of a detergent slurry.

From US Pat. No. 3,985,668, abrasives are gel-like Consistency known to be a suspending agent and preferably smectite and attapulgite types of colloid-forming Clays and abrasives such as quartz sand or perlite and ultimately fillers such as powdered polymers are less Contain dense or expanded perlite, which show a certain buoyancy and thus the mixture stabilize and also act as fiber and in the process replace the water that would otherwise produce an undesirable protruding layer formation due to exudation or a phase impairment.

In addition to these basic ingredients, such scouring agents can also be hypochlorite bleaching agents, which are bleach-stable Contain surfactants and buffer substances, silicates, carbonates and monophosphates as well as builders such as NaTPP, to support the builder effect of the buffer substances. The amount of such builders is below 5% by weight, based on the total composition. The desired pH value above 10 is set by the buffer or builder components, where

3b the high pH of chlorine bleach decomposition

and to counteract an undesirable interaction between bleach and surfactant. That if necessary NaTPP present is limited to 5% by weight; Foam pusher are not included in these products. 5

The invention has the task of proposing a new dishwashing detergent for automatic dishwashers which has thixotropic properties, shows improved chemical and physical stability and which can be easily and quickly dispersed in the washing liquid in order to effectively clean porcelain, glass and dishes . In particular, a dishwashing agent is to be proposed which is suitable for household dishwashers and which, in addition to the thixotropic or gel-like structure, contains each of the various components required for effective cleaning in such automatic dishwashers, the dishwashing _{agent having a correspondingly good} physical stability without phase separation shows even after standing for a long time, even with a strongly alkaline setting of the detergent, which is necessary for effective cleaning power; Furthermore, the new dishwashing detergent should be constructed in such a way that no undesirable interaction between the chemically active components occurs or that these only appear to a minor extent. Furthermore, the new dishwashing detergent should have better rheological properties and a higher viscosity under lower shear stress and a lower viscosity under higher shear stress, so that it can advantageously be used in the dispensing device of the dishwasher. Ultimately, the new dishwashing detergent should have a low foaming behavior, improved cleaning power and faster dispersibility in the dishwasher.

To solve this problem, a dishwashing agent according to the main claim is proposed. Particularly suitable compositions emerge from the subclaims.

The dishwasher detergents according to the invention for automatic Dishwashers are low foaming, are both chemical and physical stable and dissolve quickly in the washing liquid and are particularly effective at the pH values that give an improved cleaning effect, viz at pH values in the range from 10.5 to 13.5. The mixtures according to the invention normally have a gel consistency, i.e. they are highly viscous, opaque jelly-like products with a Bingham plasticity and thus have relatively high flow values. As a result, a certain shear force is required to prevent the outflow to effect or amplify, as one would in a dispenser of an operated or switched on Has automatic dishwasher. Under these conditions the mixture according to the invention becomes rapid brought into a fluid state and easily released. When the shear force is interrupted, the fluid mixture reverses quickly returns to its highly viscous state or into the plastic Bingham state and takes its previous consistency.

In general, the "effectiveness is that of the present invention Dishwashing detergent depends directly on the available chlorine content, the alkalinity, the solubility in the washing medium and the low foaming, it is also essential that the pH value of the mixture according to the invention is in a range from 10.5 to 13.5 and preferably at least 11.5. The use of NaOH is essential because without NaOH the pH would be below 10.5. With such a

pH, the product is too viscous or nearly solid and falls below that prevailing in the dispenser No longer easily bring shear forces into a fluid state; atone for such a means then its thixotropic properties. In this case the addition of NaOH is essential to adjust the pH to increase and to improve the flow properties. The presence of carbonate is usually required as it is used as a buffer substance to maintain the required pH range guaranteed. Excess carbonate should be avoided, otherwise needle-like Carbonate crystals form, which increase the stability and the Impair the effectiveness of the product; it also serves the existing foam pusher, namely to neutralize the phosphoric acid ester.

Further criteria for the selection to achieve a stable and effective dishwashing detergent with thixotropic Properties are as follows: The NaTPP should not contain any heavy metals because these contribute to the decomposition of the sodium hypochlorite. On average, the NaTPP contains about 5 to 15% by weight of water, corresponding to an average Degree of hydration from eta 1 to 5. If only the hexahydrate is used, the detergent is liquid and hardly has thixotropic properties. If only anhydrous NaTPP is used, the result is a too thick one and consequently unsuitable product. Excellent dishwashing detergent compositions according to the invention contain, for example, a mixture of anhydrous NaTPP and the corresponding hexahydrate in a weight ratio of 0.5: 1 to 2: 1, with a weight ratio 1: 1 is particularly preferred. The foam pusher is essential to its effectiveness.

the dishwasher increasing and destabilizing

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To prevent effects that may occur due to excessive foaming during use. The free Chlorine is through in the mixtures according to the invention the sodium hyperchlorite provided and not through the dichloroisocyanurates usually found in powder cleaning agents.

The inventive product shows an improved rheological behavior _j particular with regard to

-JO the viscosity as a function of the shear forces. The investigations confirmed that the blends of the present invention had higher viscosity at low shear forces and lower viscosity at higher shear / intrinsic, i.e. more efficient transfer to the

-15 fluid state and allows better gelation is with shear forces that occur in conventional dishwashers. This means practically that the flowing delivery and the manageability of the products is better and that at the same time this Products not undesirable from the dispenser can escape, as is the case with conventional liquid dishwashing detergents. With the occurring Shear forces of 3 to 30 rpm accordingly, Brookfield viscosities are in a range of 15 up to 30,000 cPs up to about 3000 to 5000 cPs at room temperature with an LVT Brookfield viscometer Obtained 3 minutes with a # 4 spindle. A shear rate of 7.4 seconds corresponds to one revolution of the spindle per minute of about 3. An about 10-fold increase in Shear rate gives about a 6- to 7-fold decrease in viscosity. In the known gel-like dishwashing detergents the corresponding reduction in viscosity is only about twice the value. Furthermore For these known mixtures, the initial viscosity is around 3 rpm, only around 2500 to 2700 cPs.

The mixtures according to the invention show a threshold value the fluidization at lower shear rates and to a significantly greater extent of the proportional increase the shear rate versus the proportional reduction in viscosity. This property of the invention Products is expressed by the Thixotropy Index (TI), which is the ratio of the actual viscosity at 3 rpm, to the actual viscosity at 30 rpm. The mixtures according to the invention have a TI value of about 2.5 and preferably from 6 to 8. All mixtures according to the invention showed a full and rapid return to their previous hibernation with appropriate consistency, though no more shear forces are exerted.

In the preparation of the mixtures according to the invention one should first all inorganic salts, namely the carbonates, silicates and polyphosphates in the aqueous Dissolve or disperse the medium and add the thickener as the last component. The foam-suppressing one Phosphoric acid ester is originally added as an aqueous dispersion, just like the thickener. The ester dispersion, the sodium hydroxide and the inorganic ones Salts are first at elevated temperature in aqueous solution and preferably in deionized water prepared with constant stirring and then cooled. Then the bleach, the surfactant and the dispersion of the thickener

added to the solution cooled to about 25 to 35 ° C. 30th

The amount of water is such that the concentration of the active ingredients in the invention Product is 35 to 75 wt.% And preferably 50 to 65 wt.%.

The inorganic salts are used based on the total weight of the mixture in such a way that about 5 to 35% by weight and preferably 20 to 30% by weight of NaTPP, 2.5 to 20% by weight and preferably 10 to 15% by weight of sodium silicate with a _Well? 0: SiO weight ratio of about 0.3 to 0.5 and up to 9% by weight, preferably 4 to 7% by weight, alkali metal carbonate, preferably sodium carbonate, are present. The total salt concentration ranges from about 20 to 50 and preferably up to 45 percent by weight.

The bleach is sodium hypochlorite, which is a NaOCl solution with 13% available chlorine; the bleaching agent is used in amounts of about 3 to 20 and preferential ^ ^5, 7 to 12 wt.%.

The sodium hydroxide should be present in such an amount that a pH of 10.5 to about 13 ^ 5 and preferably a pH of 11.5 to 12.7 is achieved, which in the

is generally achieved by additions of 0.5 to 3% by weight; in any case, at least as much sodium hydroxide should be used be used so that the phosphoric acid ester, which is present as a foam suppressor, is neutralized.

The preferred foam depressor is a mono- and / or di-C ._- to C. -alkyl ester of phosphoric acid, which is found in

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Amounts from 0.1 to 0.5, and preferably 0.15 to 0.3 percent by weight is present, the precise amount of which component is present in part on the amount of surfactant 30 present

depends.

The surfactants used in the agents according to the invention must be in the presence of hypochlorite bleaching agents be stable and are preferably anionic products, amine oxides, phosphine oxides or sulfoxides and betaine types, the former being preferred. They will be in abundance

from about 0.1 to 5 and preferably from 0.3 to 0.8% by weight used. In order to achieve sufficient foam pressure, the ratio from surfactant to shower pusher in a range of 10.1 up to 1: .1 and preferably 1.5: 1 to 4: 1 to be used.

Particularly suitable surfactants are linear or branched alkali mono- and / or di C to C alkyl diphenyl oxide monosulfonates or disulfonates, In general, paraffin sulfonates tend to reduce the thixotropic properties

tend to adversely affect or destroy and result in an excessive increase in viscosity, thereby difficulties regarding the required result in high shear forces. The surfactants should also

with the other components of the 15 according to the invention

Mixture be compatible. Other suitable surfactants include primary alkyl sulfates, alkyl sulfonates, alkyl aryl sulfonates, and secondary alkyl sulfates such as C8 sodium. _n to C. alkyl sulfates, such as

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Sodium dodecyl sulfate, sodium tallow alcohol sulfate, sodium

C. _n to C alkanesulfonates such as sodium hexadecyl-1-sulfοι U Io

nat, sodium C. "to C. -alkylbenzenesulfonates such as Na-

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traium dodecylbenzenesulfonate and corresponding potassium salts .

Other suitable surfactants are amine oxides of the general formula R _? R NO, where each R radical is a lower alkyl radical such as methyl, while R is a long-chain alkyl radical having 8 to 22 carbon atoms, such as a lauryl, myristyl, palmityl or cetyl group. Instead of an amine oxide, a corresponding phosphine oxide of the general

1 1

Formula R ₃ R po or a sulfoxide RR SO can be used.

Betaine-type surfactants have the general formula

1 1

RR N + R "COO-, in which R is a lower alkyl radical, R a

If "

long-chain alkyl radical as before and R ″ an alkylene radical having 1 to 5 carbon atoms. Suitable examples of these surfactants are lauryl dimethylamine oxide, Myristyl dimethylamine oxide, coconut dimethylamine oxide, hardened tallow dimethylamine oxide and the corresponding Phosphine oxides and sulfoxides as well as corresponding betaines including dodecyl-dimethylammonium acetate, tetradecyl-diethylammonium pentanoate, Hexadecyl dimethylammonium hexanoate and the same. With regard to the biological decomposability, the alkyl radicals in these should Surfactants can be linear and are therefore preferred.

Such surfactants are known in general and, for example, from US Pat. Nos. 3,985,668 and 4,271,030.

The thickening or suspending agents are generally inorganic colloid-forming clays of the smectite and / or attpulgite type, the former being preferred. These components influence the rheological properties of the mixtures according to the invention and are used in amounts of about 2.5 to 4% by weight, whereby the amount should in any case be sufficient ₍ to impart the desired Bingham plasticity to the product, smectite clays include montmorillonite (bentonite), among other things of the preferred grades such as hectorite, saponite, etc. These products are sold under the names "Thixogel No. 1" and "Gelwhite GP" by the Georgia Kaolin Company and are montmorillonites

the name "Attagel" such as "Attagel 40", "Attagel 50" and "Attagel 150" from Engelhard Minerals and Chemicals Corporation.

Mixtures of smectite and attapulgite in one weight

ratios of 4: 1 to 1: 5 are suitable.

Suspending agents of this type are known and are described, for example, in US Pat. No. 3,985,668.

Other ingredients for the dishwashing detergents according to the invention are dyestuffs for producing nicely colored products, especially chlorinated phthalocyanines and polysulfides of aluminosilicates which give green and blue colorations, respectively, are preferred.

In the following, the invention is intended to be based on examples are explained in more detail, all quantitative data being based on weight unless otherwise stated.

~ * ^ Example 1

A starting dispersion I was prepared with a foam press, which is a 2: 1 mixture of mono- and di- (C ._- C) -alkyl esters of phosphoric acid in one

Amount of 0.16 g contained in 6 g of water; it was mixed with a disk stirrer at 60 ° C. for 30 minutes.

Another dispersion II was made from a smectite

(Gelwhite GP) in an amount of 3 g in 17 g of water 25

made, taking 10 minutes at one temperature

of 70 ° C with a Z-paddle mixer.

The following ingredients were placed in a Giusti mixer 30th

mixed at 50 to 60 C.

Components

Desalinated water dispersion I NaOH solution (49%) sodium carbonate

Sodium Silicate (1: 2.4) as a 47.5% solids solution

NaTPP (anhydrous) NaTPP (hexahydrate)

Weight% active Be Weight% components 16.9 6.16 0.16 2.40 1.2 7.00 7.0 13.74 6.5 12.00 11, 54 12.00 9.36

The anhydrous NaTPP contained about 0 to 5 and usually 3 wt.% Moisture.

This mixture was cooled to 25-30 ° C. with constant stirring and then at room temperature
mixed with the following components:

20 sodium hypochlorite solution with 13% by weight active chlorine

Dispersion II surfactant

7th , 615 1 , 0 20th , 00 3 , 0 0 , 80. 0 , 36

A sodium monodecyl / didecyl disulfonated diphenyl oxide with 45% active ingredients was used as the surfactant. An opaque gel-like mixture with about 40% active ingredients was obtained, which had a TI value of about 7 or a viscosity of
28,000 cPs at 3 rpm, and 4,000 cPs at 30 rpm. In an automatic dishwasher with a dispensing device, the mixture according to the invention exhibited excellent cleaning behavior; it was easy and quick to deliver. The dishwashing detergent according to the invention showed no foam. After prolonged storage

the product in a closed container no or practically no phase separation observed. The pH of the detergent was 1% aqueous solution 11.6. The behavior under shear conditions was excellent; after removal of shear forces the product resumed its resting consistency very quickly, which shows that the flow behavior was not influenced by the given load. There was also no discernible difference when dispensing the product from a tube, compared to the dispensing from the dispensing device of a dishwasher .

When there is a change in the composition of the product

-4 ₅ according to Example 1 that contained a total concentration of polyphosphate, carbonate and silicate of about 37%, by changing the total concentration of these salts within the specified ranges, the best results were obtained with a combined salt concentration ^of at least about 30% by weight, especially when the concentration of sodium tripolyphosphate was at least about 20 % . Higher silicate concentrations to achieve better protection of the porcelain glaze and the decoration lead to a higher alkalinity, which can be compensated by reducing the NaOH concentration or adjusting the concentration of the sodium carbonate, which acts as a buffer, accordingly. The composition is clearly responsive to changes in NaTPP concentration in the sense that higher concentration yields more effective products; it also clearly responds to the degree of hydration. Changes in the concentration of surfactants generally require a corresponding and direct change in the concentration of the foam suppressor in order to maintain the desired low foam area.

A decrease in pH below 10.5 leads to a noticeable decrease in effectiveness and flowability.

If, in a mixture according to Example 1, alkyl sulfate is used as surfactants, such as sodium coconut alkyl sulfate and attapulgite clay or a 2: mixture of montmorillonite and attapulgite clay (for example Attagel 50) gives similar results.

By adding smaller amounts of 0.003 to 0.05% by weight chlorinated phthalocyanine or aluminosilicate paints turn green or blue colored mixtures obtain. The dyes are added with the thickening dispersion II or the cooled solution on Added at the end.

Claims (1)

U EXKULl; Λ STDLÖt ^ G P AI E N TΛ WyJ LT £ BESELERSTRASSE 4 D-2OOO HAMBURG 52 'EUROPEAN PATENT ATTORNEYS DR. JD. FRHR. by UEXKÜLL DR ULRICH GRAF STOLBERG DIPL.-ING JÜRGEN SUCHANTKE DIPL-ING ARNULF HUBER DR. ALLARD by KAMEKE DR KARL-HEINZ SCHULMEYER Colgate-Palmolive Company 300 Park Avenue New York, N.Y. 10022 V.St.A. (Priority: Jan. 18, 1982 US 339 915 and January 10, 1983 US 445 983 - 19336 / UE / where) January 1983 Water-based dishwashing detergent for automatic dishwashers 1. Aqueous-based dishwashing detergent for automatic winding machines, characterized by a Content of a) 5 to 35 wt.% Alkali metal tripolyphosphate with a average degree of hydration of about 1 to 5; b) 2.5 to 20% by weight sodium silicate; c) 0 to 9% by weight of water-soluble alkali metal carbonate; d) 0.5 to 5% by weight of a water-dispersible, bleach-resistant organic surfactant; e) 0.1 to 0.5% by weight of a mono- and / or di-C ₁ - to C _R -alkyl ester of phosphoric acid as a foam depressant; f) 3 to 20% by weight of a NaOCl solution with about 13% available chlorine; g) 1.5 to 10% by weight of an inorganic, colloid-forming clay thickener and h) Sodium hydroxide to adjust the pH from 10.5 to 13.5, where the amount of the phosphoric acid ester is sufficient to cause a slight foam build-up. to give, and the amount of sodium hydroxide is at least sufficient to the phosphoric acid ester to neutralize, and that the thixotropy index of the detergent is about 2.5-10. 2. Dish washing agent according to claim 1, characterized in that the weight ratio of surfactant to foam pusher is about 10: 1 to 1: '1. 3. Dishwashing agent according to claim 1, characterized in that that the total concentration of tripolyphosphate, silicate and carbonate is at least 20% by weight amounts to. 4. dishwashing agent according to claim 3, characterized in that that the concentration of tripolyphosphate is about 20 to 30% by weight. 5. Dishwashing agent according to claim 1, characterized in that that the tripolyphosphate consists of a 33002A3 mixture of essentially anhydrous tripolyphosphate and a tripolyphosphate hexahydrate in a weight ratio of about 1: 2 to 2: 1, and preferably 1: 1. 5 6. dishwashing detergent according to claim 1, characterized in that it contains a dye for coloring contains sufficient quantity. 7. dishwashing agent according to claim 1, characterized in that that the thickener is a smectite and / or attapulgite clay. 8. Dish washing agent according to claim 1, characterized in that the surfactant is an alkali C _ß to C ..- A1- is kyldiphenyl oxide sulfonate. 9. dishwashing detergent according to claim 1, characterized in that the tripolyphosphate is a sodium tripolyphosphate, the carbonate is a sodium carbonate and the surfactant is a mixture of mono- and di (C to C alkyl) diphenyloxide disulfonate and that the thickener is bentonite. 10. Dish washing agent according to claim 9, characterized in that the pH is 11.5 to 12.7 and the thixotropy index has a value of 6 to 8.