EP0014980B1 - Mechanically applicable combined dish washing and rinsing agent and process for simultaneously cleaning and rinsing dishes in dishwashing machines - Google Patents

Description

The invention relates to a means for the simultaneous machine cleaning and rinsing of dishes and a method for the simultaneous cleaning and rinsing of dishes in dishwashers.

As is well known, the automatic cleaning of dishes takes place in several individual steps, generally called "courses," with one or more intermediate rinsing cycles with clear water between the actual cleaning cycle and the final rinse cycle in order to reduce the carryover of lye. Two different agents, namely a dishwashing detergent (cleaner) and a rinse aid (rinse aid), are usually used for the cleaning and rinse cycle (Ullmanns Encyklopadie der Technische Chemie, 14, (1963), page 656).

The cleaner has the task of swelling the food residues during the cleaning cycle of the dishwasher, detaching them from the dishes and dispersing them in the detergent fleet.

In the last rinse, the dishes are washed with the addition of rinse aid. Due to its composition, the rinse aid has the task, on the one hand, of relaxing the water, so that the water forms a closed, increasingly thinner film on the surface of the dishes, which then peels off, and, on the other hand, of ensuring that the dishes are uniform after drying Has gloss.

With the use of this two-person combination of a detergent and a rinse aid, even delicate dishes are cleaned gently and perfectly in modern dishwashers and washed dry. However, it is perceived as a disadvantage that the use of two different agents is always essential for a good result and should preferably also be specifically coordinated with one another.

There was therefore the task of developing a product which, when used in the dishwasher, and at the same time, in particular with a single addition, fulfilled the task of the conventional two-way combination of a detergent and a rinse aid.

The object is achieved by a machine-applicable powder dishwashing detergent with a content of condensed phosphates, silicates, alkalis, nonionic surfactants, active chlorine-releasing compounds and water-soluble organic polymers which is characterized in that it is - based on the total weight of the above-mentioned constituents, including any adhesives present Water or water of hydration - as nonionic surfactant 0.5-5, preferably 0.8-2 percent by weight of an ethoxylated and then propoxylated fatty alcohol and as water-soluble organic polymers 0.2-2.5, preferably 0.8-1.2 percent by weight of polyethylene glycols an average molecular weight between 300,000 and 4,000,000, preferably between 500,000 and 1,000,000.

Machine-applicable powder dishwashing detergents containing condensed phosphates, silicates, alkalis, ethoxylated and propoxylated fatty alcohols, active chlorine-releasing compounds and water-soluble organic polymers are already known from DE-A 25 01 529. Anionic organic polymers, namely the sodium salt of poly-a-hydroxyacrylic acid, were then used to reduce the surface corrosion of the wash ware caused by sodium tripolyphosphate. A corresponding teaching can also be found in DE-A 24 35 479. This does not make the use of rinse aid after the automatic cleaning cycle of the dishwasher unnecessary.

According to the teaching of GB-A 1,527,706, additions of water-soluble polyacrylates also serve to condition surfactant-free alkaline aqueous cleaning pastes which can be fed into dishwashers in this form. But there is no simultaneous rinse aid effect there either. H. to achieve a quick water drainage with resulting, like shiny new dishes.

US Pat. No. 3,825,498 teaches that the phosphate content in detergents causing water reutrophication can be reduced or eliminated by adding relatively large amounts of polyhydroxycarboxylic acids or their salts. These are also anionic polymers that are able to act on the metal ions causing the water hardness. This also results in mere cleaning agents for dishes without simultaneous rinse aid.

The nonionic surfactants mentioned are known in a known manner by reacting about one mole of a mixture of C ₁₂ -C ₁₈ , preferably C, 2-C1, fatty alcohols with 1, preferably 1-3, moles of ethylene oxide and then 2-7, preferably 4 -6 moles of propylene oxide produced.

The polyethylene glycols are prepared in a known manner, namely, for example, by subjecting ethylene glycols to a polycondensation process. They can also be considered as condensation polymers of ethylene oxide with ethylene glycol or water. They have the general formula HO (-CH2-CH2-O) nH, where n can vary between 4,800 and 64,000 in the case of the polyethylene glycols used according to the invention. Such polymers are also commercially available and are sold by Union Carbon Carbide Corporation (UCC) under the registered trademark "POL YOX @".

• 20-55 vorzugsweise 30-45 % eines wasserlöslichen kondensierten Alkaliphosphats,
• 30-60 vorzugsweise 35-40 % eines Alkalimetasilikats,
• 2-15 , vorzugsweise 5-10 % eines Alkalihydroxids und/oder eines Alkalicarbonats,
• 0- 8 vorzugsweise 3-5 % eines wasserlöslichen Alkalisilikats,
• 1-10 , vorzugsweise 1,5-5 % einer aktivchlorabspaltenden Verbindung,
• 0,5- 5 , vorzugsweise 0,8-2% eines ethoxylierten und anschließend propoxylierten Fettalkohols,
• 0,2-2,5, vorzugsweise 0,8-1,5 % eines wasserlöslichen Polyethylenglycols mit einem mittleren Molgewicht zwischen 300.000 und 4.000.000, vorzugsweise zwischen 500.000 und 1.000.000, sowie
• 0 -20 % Wasser.

The agents according to the present invention are based on 100% total weight (% = Ge percent by weight), essentially from:

• 20-55 preferably 30-45% of a water-soluble condensed alkali phosphate,
• 30-60 preferably 35-40% of an alkali metal silicate,
• 2-15, preferably 5-10% of an alkali hydroxide and / or an alkali carbonate,
• 0-8 preferably 3-5% of a water-soluble alkali silicate,
• 1-10, preferably 1.5-5% of an active chlorine-releasing compound,
• 0.5-5, preferably 0.8-2% of an ethoxylated and then propoxylated fatty alcohol,
• 0.2-2.5, preferably 0.8-1.5% of a water-soluble polyethylene glycol with an average molecular weight between 300,000 and 4,000,000, preferably between 500,000 and 1,000,000, and
• 0 -20% water.

Condensed phosphates suitable for the purposes of the invention are the water-soluble alkali metal salts of di- or triphosphoric acid or the water-soluble alkali metal hexametaphosphates which are usually used as complexing agents in dishwashing detergents.

Sodium or potassium metasilicates are used as alkali metal silicates, in which the ratio of alkali oxide to silicon dioxide is 1: 0.9 to 1: 1.5. These compounds are preferably anhydrous. However, they can contain 4.70 to 5 moles of water of crystallization.

Suitable alkali metal hydroxides or alkali metal carbonates are primarily sodium or potassium hydroxide or the corresponding carbonates.

Insofar as water-soluble alkali silicates are used in the mixtures, they are those in which the ratio of alkali oxide to silicon dioxide is approximately 1: 1.5 to 3.8 and which are generally known as sodium or potassium water glass.

Trichloroisocyanuric acid or its alkali metal salts, e.g. B. potassium and sodium dichloroisocyanurate or their dihydrates or mixtures thereof. Also come alkali and alkaline earth hypochlorites, such as lithium, sodium or calcium hypochlorite as well as complex salts containing hypochlorites, e.g. so-called chlorinated phosphates, trichloromelamine, chloramine T and other active chlorine-releasing compounds. Unless stated otherwise, the amounts stated in the description of the invention relate to salts free of hydrated water.

In addition to the constituents mentioned, the claimed mixtures may optionally contain smaller amounts of further components, in particular inorganic salts such as sodium sulfate or sodium chloride. Other possible additives are substances with a buffering action, such as sodium acetate, dyes, perfumes, and corrosion inhibitors, such as sodium and calcium compounds, e.g. B. NaOH and Ca (OH) _{2 '} zeolites. This would inevitably reduce the proportion of the building blocks of the funds accordingly if all the components were to be 100 percent by weight.

The claimed powdery compositions can be packaged in a known manner by grinding and mixing the constituents. In order to achieve an intimate connection of the powder constituents, it may be appropriate to mix the powder with an aqueous solution of crystallizing salts, e.g. B. sodium sulfate or one of the nonionic surfactants mentioned. This treatment also reduces the tendency of the powder to dust.

In order to ensure the free-flowing properties of the powder mixtures obtained over a long period of time, it is also possible, as described in DE-A 21 34 695, to add hydrophilic microcrystalline silica.

The granulation of the constituents of the agents according to the invention by a process as described in DE-B 2829114 has proven to be particularly advantageous.

The claimed detergent combinations are characterized by a high cleaning ability. They are particularly suitable for removing burnt-on, protein-containing food residues, lipstick marks and tea stains. They are able to prevent the formation of starch deposits on the tableware surfaces or to remove existing coverings again. Particularly noteworthy is the low corrosion effect of the claimed mixtures, particularly in the case of porcelain overglaze decorations.

The claimed agents can be used both in household dishwashers and in commercial dishwashers. It is added by hand or using suitable dosing devices. The application concentrations in the cleaning liquor are about 0.5-10, preferably 2-5 g / l. The pH values of the cleaning liquors are between pH 7-13, preferably pH 8-12.

The advantage of the claimed agents is that no rinse aid needs to be added in the last rinse, but only rinsed with pure tap water and still a rinse aid result is achieved that is at least as good or even better than that of the conventional method using the two-way combination of a detergent and a rinse aid. This simplifies the handling of the dishwasher, because after the cleaning cycle using the new dishwashing detergent alone, it is sufficient for a perfect washing result to rinse the dishes with clear water and then dry them as usual. After drying you get a completely clean and hygienically perfect dishes.

The present invention therefore also relates to a method for the simultaneous machine cleaning and rinsing of dishes, which is characterized by the use and the one-time and sole addition of the claimed agents in the cleaning cycle of a dishwasher.

By simplifying control and saving the dosing device for the rinse aid, cheaper household dishwashers could be built. The alternating stress caused by the constant action of alkaline cleaners and acidic rinse aids on the dishes is eliminated; porcelain frosting decorations, glasses, knife blades and the like are protected even more than before.

However, the statements made above do not limit the possible uses of the agents according to the invention to such simpler dishwashers. In all previous dishwashers with rinse aid dosing, the sole use of the claimed agents achieves excellent cleaning and rinse aid results without the additional use of the usual rinse aid.

To the examples

The cleaning results and clear drying effects of the claimed cleaning-detergent combinations were checked in the so-called normal program of a standard household dishwasher, a Miele G 503.

To test the cleaning results, glass dishes with the burnt-on food residues of milk, chocolate pudding or minced meat as well as plates with dried residues of porridge or starch and cups with dried residues of tea (according to the publication "Testing detergents and rinse aids for machine dishwashing in soaps -Ölen-Fette-Wwachs, 98, (1972), pages 763 ff and 801 ff) in the household dishwasher with 3 g detergent per liter of washing liquor in the cleaning cycle. The soiling is selected so that removal with other conventional cleaners which have a high cleaning power is only partially possible in order to still have differentiation options even with these high-performance products. For the individual evaluations, a point system was used, which ranges from 0-10, whereby 0 points mean "without recognizable cleaning effect and 10 points" completely eliminating the test soiling.

To test the clear dry effects, 4 knives each made of C _18/10 chrome nickel steel, 6 porcelain plates and 6 glasses of 3 or 6 g / l of standard soiling, consisting of a mixture of 100 g margarine, 50 g raw egg, 50 g spinach, 100 g of skimmed milk, 100 g of oatmeal, 200 g of mashed potatoes and 400 g of gravy, which was added directly to the washing-up liquor of the household dishwasher, exposed and also treated with 3 g detergent-detergent combination per liter of washing liquor in the cleaning cycle.

A point system of 0-10 was also used for the evaluation of the clear dry effect on the glasses, whereby 0 points mean «completely inadequate clear drying (stripes, stains, etc.) and 10 points« perfect clear drying (high-gloss glasses without streaks and stains). The mean values of the cleaning and clear dryer results were determined for each mixture from double experiments. For comparison, the mean values of the cleaning and clear drying effects of a commercial rinse aid and an inventive detergent combination using a commercial rinse aid were also determined.

The commercial cleaner had the following composition: 36% sodium tripolyphosphate, 39% sodium metasilicate, 6% sodium carbonate, 2% sodium dichloroisocyanurate, 1% nonionic surfactant and 16% water. It was used at a concentration of 3 g / 1 liquor.

The commercial rinse aid was composed of 15% of a nonionic surfactant and 20% citric acid in aqueous alcoholic solution and was used in a concentration of 0.3 g / l of liquor.

example 1

• 37 % Pentanatriumtriphosphat,
• 40 % Natriummetasilikat mit einem Verhältnis von Natriumoxid zu Siliciumdioxid wie 1 : 0,98 ; wasserfrei,
• 6,5 % Natriumcarbonat; wasserfrei,
• 3,9 % Natronwasserglas,
• 2,25 % Natriumdichlorisocyanurat . 2H₂0,
• 1,0 % C12-C14-Fettalkohol, umgesetzt mit 1 Mol Ethylenoxid und anschließend mit 6 Mol Propylenoxid,
• 1,0 % Polyethylenglycol MG 500 000,
• Rest % Wasser.

It was rinsed with a detergent-detergent combination of the following composition without using a rinse aid:

• 37% pentasodium triphosphate,
• 40% sodium metasilicate with a ratio of sodium oxide to silicon dioxide such as 1: 0.98; anhydrous,
• 6.5% sodium carbonate; anhydrous,
• 3.9% soda water glass,
• 2.25% sodium dichloroisocyanurate. 2H ₂ 0,
• 1.0% C12-C14 fatty alcohol, reacted with 1 mol ethylene oxide and then with 6 mol propylene oxide,
• 1.0% polyethylene glycol MG 500 000,
• Rest% water.

For comparison, rinsing was carried out with the commercially available detergent using a commercially available rinse aid of the recipes given at the outset and with the commercially available rinse aid without using the rinse aid. The following mean values of the cleaning and clear drying results were determined from the tests:

As these results show, the use of a rinse aid when using the detergent combination according to the invention is superfluous, while it is absolutely necessary when using a commercially available detergent.

Example 2

• 40,0 % Pentanatriumtriphosphat,
• 33,0 % Natriummetasilikat mit einem Verhältnis von Natriumoxid zu Siliciumdioxid wie 1 : 0,98 ; wasserfrei,
• 5,0 Natriumcarbonat; wasserfrei,
• 1,5 % Trichlorisocyanursäure,
• 5,0 % eines schwachschäumenden, nichtionogenen Tensids aus der Klasse der ethoxylierten und propoxylierten Fettalkohole mit von 12 bis 15 Kohlenstoffatomen,
• 2,0 % Polyethylenglycoi MG 500.000,
• Rest % Wasser.

It was rinsed with a detergent-detergent combination of the following composition without using a rinse aid and with 3 g test soiling:

• 40.0% pentasodium triphosphate,
• 33.0% sodium metasilicate with a ratio of sodium oxide to silicon dioxide such as 1: 0.98; anhydrous,
• 5.0 sodium carbonate; anhydrous,
• 1.5% trichloroisocyanuric acid,
• 5.0% of a low-foaming, nonionic surfactant from the class of ethoxylated and propoxylated fatty alcohols with from 12 to 15 carbon atoms,
• 2.0% polyethylene glycol MG 500,000,
• Rest% water.

The following mean values of the cleaning and clear drying results were determined from the tests:

Example 3

• 40,0 % Pentanatriumtriphosphat,
• 40,0 % Natriummetasilikat mit einem Verhältnis von Natriumoxid zu Siliciumdioxid wie 1 : 0,98 ; wasserfrei,
• 10,0 % Natriumcarbonat; wasserfrei,
• 2,0 % Natriumhypochlorit,
• 2,0 % Wasserglas,
• 3,0 % eines schwachschäumenden, nichtionogenen Tensids aus der Klasse der ethoxylierten und propoxylierten Fettalkohole mit 12 bis 18 Kohlenstoffatomen,
• 0,8 % Polyglycolether MG 1.000.000,

In this example, the rinse was carried out as in Example 2 without using a rinse aid. The detergent mixture had the following composition:

• 40.0% pentasodium triphosphate,
• 40.0% sodium metasilicate with a ratio of sodium oxide to silicon dioxide such as 1: 0.98; anhydrous,
• 10.0% sodium carbonate; anhydrous,
• 2.0% sodium hypochlorite,
• 2.0% water glass,
• 3.0% of a low-foaming, nonionic surfactant from the class of ethoxylated and propoxylated fatty alcohols with 12 to 18 carbon atoms,
• 0.8% polyglycol ether MG 1,000,000,

Rest of water.

Claims (4)

1. A powder-form dish-washing preparation suitable for use in dish-washing machines and containing condensed phosphates, silicates, alkalis, nonionic surfactants, active chlorine donors and water-soluble organic polymers, characterised in that it contains a nonionic surfactant from 0.5 to 5 % by weight and preferably from 0.8 to 2 % by weight of an ethoxylated and subsequently propoxylated fatty alcohol and, as water-soluble organic polymers from 0.2 to 2.5 % by weight and preferably from 0.8 to 1.2 % by weight of polyethylene glycols having an average molecular weight of from 300,000 to 4,000,000 and preferably from 500,000 to 1,000,000 - based in each case on the total weight of the above-mentioned constituents, including any adhering water or water of hydration present.

2. A preparation as claimed in Claim 1, characterised in that it contains as nonionic surfactant a C₁₂-C₁₈ and preferably a C₁₂-C₁₄ fatty alcohol mixture reacted (per mole) with from 1 to 5 moles and preferably with from 1 to 3 moles of ethylene oxide and subsequently with from 2 to 7 moles and preferably with from 4 to 6 moles of propylene oxide.

3. A preparation as claimes in Claims 1 and 2, characterised in that it consists essentially of :

from 20 to 55 and preferably from 30 to 45 % by weight of a water-soluble condensed alkali phosphate,

from 30 to 60 and preferably from 35 to 40 % by weight of an alkali metasilicate,

from 2 to 15 and preferably from 5 to 10 % by weight of an alkali hydroxide and/or alkali carbonate,

from 0 to 8 and preferably from 3 to 5 % by weight of a water-soluble alkali silicate,

from 1 to 10 and preferably from 1.5 to 5 % by weight of an active chlorine donor,

from 0.5 to 5 and preferably from 0.8 to 2% by weight of anb ethoxylated and subsequently propoxylated fatty alcohol,

from 0.2 to 2.5 and preferably from 0.8 to 1.5 % by weight of a water-soluble polyethylene glycol having an average molecular weight of from 300,000 to 4,000,000 and preferably from 500,000 to 1,000,000 and

from 0 to 20 % by weight of water.

4. A method for simultaneously washing and rinsing dishes in a dish-washing machine, characterised by the use of and the single and sole addition of the preparation claimed in Claims 1 to 3 in the washing cycle of a dishe-washing machine.