EP0663943A1

EP0663943A1 - Clear rinse for machine dish washing

Info

Publication number: EP0663943A1
Application number: EP93920836A
Authority: EP
Inventors: Jürgen Härer; Theodor Altenschöpfer; Peter Jeschke; Christian Nitsch
Original assignee: Henkel AG and Co KGaA
Current assignee: Henkel AG and Co KGaA
Priority date: 1992-10-07
Filing date: 1993-09-28
Publication date: 1995-07-26
Also published as: CA2146535A1; JPH08501817A; WO1994007977A2; DE4233699A1; US5602093A; WO1994007977A3

Abstract

A clear rinse for machine dish washing contains alkyl polyglycosides of the formula CnH2n+1-O-(C6H10O5)xH where n = 8-16 and 1 < x < 3, together with optionally modified alkyl polyglycol ethers of the formula C8-C18-OR + x EO where R = H, CmH2m+1 m = 1-4 and x = 1-15, preferably 2-10, or mixtures of these alkyl polyglycol ethers and organic carboxylic acids.

Description

"Rinse aid for automatic dishwashing"

The international application WO889 / 09369 describes liquid aqueous agents for machine cleaning of dishes which contain 0.5 to 20% by weight of a mixture of alkyl polyglycosides of the formula R - O - (Z) _x H with R = C ₈ - C ₁₆ alkyl, Z = glucose unit and x = 1 - 3, preferably 1 - 2, and in particular 1 - 1.4 and low-foaming nonionic surfactants of the formula R ₁ -O- (EO) _n (PO) _m H with R ₁ = C ₆ -C ₂₂ alkyl, n = 1-40 and m = 1-15 and 10 to 60% by weight of alkali metal citrates. Such cleaning agents are unsuitable as rinse aid.

It is known that when using modern phosphate-free and low-alkaline cleaners for automatic dishwashing, limescale or silicate deposits can form on the dishes and in the interior of the machine, since the calcium binding capacity of these cleaners is lower than that of the classic phosphate-containing products. Disturbing lime or silicate deposits occur in particular if the washing water in the dishwasher is not or not sufficiently softened and a water hardness of 4 ° dH is exceeded. In such cases, limescale or silicate deposits can be effectively avoided if citric acid is dosed into the rinse aid via the rinse aid. However, since the amounts of rinse aid normally added during the rinse cycle with 3 ml - 6 ml are very small, the citric acid content in rinse aid formulations which are to ensure effective deposit inhibition must be relatively high in order to achieve sufficient acid or complexing capacity. Such high citric acid levels support the effect of the phosphate substitutes and ensure spotless dishes.

In European patent application 432836 (Unilever), rinse aid formulations for machine dishwashing are described which contain only one surfactant and only alkyl polyglycosides and as a further Be Ingredients contain defoamers and thickeners. The usual acid levels in rinse aid are missing.

Defoamers are a necessary part of these formulations, since alkyl polyglycosides are generally strong foaming agents and, in the rinse aid formulations described, would cause an unacceptable foam load when used in the dishwasher. However, defoamers are only effective if they do not dissolve in the medium to be defoamed. Therefore, the alkyl polyglycoside solutions and the defoamers in the rinse aid examples listed are not miscible with one another. There would therefore be two phases if a thickener which ensured a certain homogenization had not been used to disperse them.

However, a disadvantage of such a formulation remains the latent inhomogeneity caused by the defoamer. Defoamer and surfactant solution in the rinse aid separate after a short period of storage despite the thickener content. Such a product is understandably unsuitable for customers of branded goods and for large-scale consumption, because it requires products that have to be stable in storage over a longer period of time, but at least for a year. Thus, only single-phase formulations come into consideration, in which all recipe components are homogeneously dissolved and which not only remain stable in storage, but also do not separate during the cooling cycle of the washing cycle, i.e. there must be a phase stability in the temperature range of the dishwasher of 0 ° C - 65 ° C can be guaranteed. The low temperature is necessary because warehouses are usually not heated in winter. Temperatures around freezing are therefore quite realistic. On the other hand, as long as they are homogeneous, the known products are so viscous that they cannot be poured in via the rinse aid dosing device of a household dishwasher.

Rinse aid formulations that contain only alkyl polyglycosides as a surfactant component do not wet the rest of the plastic wash ware or only very little, so that the rinse aid or drying effect is not satisfactory with these materials.

For use in detergents, i.e. also in rinse aid formulations, only recipe components that are completely biodegradable according to the Detergent and Detergent Act are suitable today. The aim of the present invention was therefore to find an ecologically and toxicologically perfect formulation which, however, provides the same results in terms of the application properties as rinse aid available on the market and does not have the disadvantages mentioned above.

Surprisingly, it was found that mixtures of alkyl polyglycosides and alkyl polyglycol ethers or mixtures of alkyl polyglycosides and modified alkyl polyglycol ethers (end-capped fatty alcohol ethoxylates) or mixtures of alkyl polyglycosides, alkyl polyglycol ethers and modified alkyl polyglycol ethers with organic carboxylic acids do not have such disadvantages with regard to a biological product, but rather the requirements of a biological product Complete degradation as well as the application properties.

Another advantage of the rinse aid according to the invention is that for the preparation of their homogeneous solutions no further, mostly inert and therefore ineffective solubilizers for drying and the rinse aid effect, such as. B. sodium cumene sulfonate or ethanol or glucose syrup are required, unless they are required in small quantities for the incorporation of colorants and / or fragrances.

The present invention thus relates to rinse aid for machine washing of dishes based on alkyl polyglycosides of the general formula C _n H _{2n + 1} -O- (C ₆ H ₁₀ O ₅ ) _x H with n = 8-16 and 1 <x <3 , which are characterized in that they additionally contain alkyl polyglycol ethers and / or modified alkyl polyglycol ethers and organic carboxylic acids. Short-chain alkyl polyglycosides (C ₈ -C ₁₂ ), such as, for. B. APG ^(R) 225 (Henkel), Lutensol ^(R) GD 70 (BASF). The amount of alkyl polyglycoside in the rinse aid according to the invention is about 0.5 to 15, preferably about 1 to 10,% by weight. Suitable alkyl polyglycol ethers are compounds of the general formula C12Ci8 ~ 0- (E0) xH (EO = ethylene oxide), where x is an integer from 1 to 15, preferably 2 to 10. They are used in amounts of about 1 to 20, preferably from about 3 to 10,% by weight. Suitable alkyl polyglycol ethers are, for example, Henkel's dehydol types such as Dehydol ^(R) LS 2, Dehydol ^(R) LS 4, Dehydol ^(R) LS 5 and Dehydol ^(R) LT 2, Dehydol ^(R) LT 3 and Dehydol ^{(R )} LT 4. The Dehydol ^(R) products of the LS series are EO adducts with fatty alcohols with a chain length in the range C12-C14 and the LT series are those in the chain length range C ₁₂ -C ₁₈ . Also suitable are dehydol ^(R) 100 (Ci2-Ci8 fatty alcohol * 9 E0) and dehydol ^(R) 980 (Cιo-Ci4 fatty alcohol * 6 E0). Modified alkyl polyglycol ethers are e.g. B. with a butyl group end-capped alkyl polyglycol such as. B. Dehypon ^(R) LS 104, Dehypon ^(R) LT 104 and Dehypon ^(R) LT 054 from Henkel.

The weight ratio of alkyl polyglycosides to alkyl polyglycol ethers is about 3: 1 to 1: 1.5, preferably about 2: 1 to 1.5: 1.

As organic carboxylic acids come aliphatic hydroxy-di- and tricarboxylic acids such as malic acid (monohydroxysuccinic acid), tartaric acid (dihydroxysuccinic acid); saturated aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid; Gluconic acid (hexane-pentahydroxy-1-carboxylic acid), but preferably anhydrous citric acid. They are used in amounts of about 1 to 50, preferably from about 1 to 30,% by weight.

Examples of performance testing of rinse aid formulations:

I. Examination of the foaming behavior of the rinse aid formulations;

The foam development of the rinse aid was determined with the aid of a circulating pressure measuring device. The rinse aid (3 ml) was dosed by hand in the rinse aid at 50 ° C.

Here mean:

0 points = no foam development

1 point = weak foaming

2 points = medium foam development (still acceptable)

3 points = strong foaming

II. Drying:

The dishwasher door was fully opened 15 minutes after the end of the washing program. After 5 minutes the drying was determined by counting the remaining drops on the dishes listed below.

Rating:

0 points = more than 5 drops

1 point = 5 drops

2 points = 4 drops

3 points = 3 drops

4 points = 2 drops

5 points = 1 drop

6 points = 0 drops (optimal drying)

III. Rinse aid effect:

After the drying had been assessed, the dishes were placed outside the dishwasher for 30 minutes to cool and then visually checked under lighting in a black box. The dried residual drops, streaks, deposits, cloudy films etc. remaining on the dishes and cutlery were assessed. Rating:

0 points = poor rinse aid effect

8 points = optimal rinse aid effect

For the performance tests II. And III. The tests were carried out in the Bauknecht GSF 1162 dishwasher with softened water. The 65 ° C normal program was selected for this. 40 ml of Somat ^(R) cleaner (Henkel) were dosed into the cleaning cycle. The amount of rinse aid - the rinse aid composition given in each case in Table 1 - was 3 ml and was dosed by hand at 50 ° C. in the rinse aid cycle. The salt load in the water was between 600 and 700 mg / 1. 3 rinse cycles were carried out for each rinse aid formulation.

The following dishes were used to assess the drying and rinse aid effects:

- "Neckar-Becher" glasses (Schott-Zwiesel), 6 pieces

- Stainless steel knife "Brasilia" (from WMF), 3 pieces

- White Prozellan dinner plates (from Arzberg), 3 pieces

- red plastic plate "Valon dinner plate" (Fa. Haßmann), 3 pieces

In all cases, the agents according to the invention were compared with those according to EP 432 836 and an alkylpolyglycoside-free formulation. Here mean:

APG ^(R) 225: alkyl polyglycoside (from Henkel); Alkyl chains n = C _8-10 , x

= 1.6

APG ^(R) 600: alkyl polyglycoside (from Henkel); Alkyl chains n = C ₁₂ -C ₁₄ , x = 1.4

Lutensol ^(R) GD 70: alkyl polyglycoside (from BASF)

Dehypon ^(R) KE 2429: defoamer (from Henkel), long-chain ketone

dispersed in a branched fatty alcohol Keltrol ^(R) F: Thickener: high molecular polysaccharide

Keltrol ^(R) S: xanthan gums

A - D: State of the art

1 -4: Comparison recipes

5- 11: Comparative recipes

HGSM: Household dishwasher

IV. Belaqsinhibitory Effects of Rinse Aid Formulations:

The deposit-reducing effect of the rinse aid formulations according to the invention was checked under the following conditions:

Commercial, phosphate-free, low-alkaline cleaners (Calgonit ^(R) Milde Kraft / Benckiser, Sun ^(R) Progress / Lever, Somat ^(R) 2000 / Henkel) were used in the cleaning cycle under hard water conditions (16 ° dH) without an adequate softening system. Lime deposits and lime stains formed on the crockery parts and in the interior of the dishwasher, which were reduced or eliminated in the subsequent rinse cycle by the rinse aid according to the invention. The following test conditions were chosen:

Dishwasher: Bosch S712

Program: 65 ° C normal program

Water: hard 16 ° dH (Düsseldorf city water)

Rinse aid dosage: 3 ml

Detergent dosage: 20 ml

The toppings remaining after the rinse cycle were assessed according to a points scheme:

0 points = no toppings

10 points = strong rubbers

Table 2:

Drying of the dishes / rinse aid effect

Recipe glasses knives porcelain plastic more common

Rinse aid *) 4.4 / 5.8 4.0 / 7.0 5.2 / 8.0 5.0 / 5.5

1 1.5 / 5.2 3.4 / 6.3 3.8 / 7.1 0 / 0.3

2 0.9 / 5.1 3.0 / 7.0 3.6 / 7.0 0 / 1.2

3 0.7 / 4.8 3.4 / 7.1 3.8 / 7.0 0 / 1.1

4 1.4 / 4.2 3.3 / 7.1 4.3 / 7.4 0 / 1.1

5 3.4 / 6.1 3.3 / 6.7 4.6 / 7.6 2.8 / 6.0

6 3.7 / 6.4 3.3 / 6.1 4.4 / 7.4 3.1 / 5.9

7 4.3 / 6.8 4.3 / 6.1 4.6 / 7.6 2.5 / 5.8

8 3.3 / 6.4 3.8 / 6.7 4.5 / 7.3 3.3 / 6.0

9 - / - - / - - / - - / -

10 - / - - / - - / - - / -

11 4.8 / 5.8 4.4 / 6.3 5.0 / 8.0 5.0 / 7.2

A 1.4 / 4.9 2.5 / 6.4 3.1 / 1.8 0 / 1.8

B - / - - / - - / - - / -

C 2.7 / 5.0 2.7 / 6.1 4.0 / 3.6 0 / 3.6

D 3.3 / 5.7 2.8 / 5.7 3.6 / 4.5 0 / 4.5

Somat ^(R) Citrus Rinse Aid (Henkel Company)

Table 1 shows the composition and foam development of the formulations 1-11 according to the invention and the formulations according to the prior art A - D during the rinse cycle. The rinse aid (recipes A, C, D) formulated with defoamer according to EP 432836 did not cause foaming. But also recipes 1 - 4, which were formulated exclusively with APG ^(R) 225, only resulted in a low and tolerable foam formation in the household dishwasher. In contrast to formulation 1, the defoamer-free formulation with the APG 60θ ^(R) (B) resulted in strong, intolerable foam formation. Formulations 5-11, the A combination of APG ^(R) 225 with alkyl polyglycol ethers with different ethylene oxide contents showed a foam development dependent on the EO content. Alkyl polyglycol ethers with an EO content of less than 7 were acceptable. At higher EO contents, strong, unacceptable foaming occurred during the rinse cycle.

Table 2 shows the drying effect of formulations 1-11 and A, C and D. This table shows that the drying effect was best for rinse aid formulations containing an APG / alkylpolyglycol ether combination or a combination of APG / alkylpolyglycol ether and modified alkylpolyglycol ether. This advantage in terms of application is particularly evident in the case of plastic tableware.

Table 2 also shows the rinse aid effect of formulations 1-11 and A, C and D. The rinse aid effect was significantly better for formulations 5 - 8 and 11, which contained APG ^(R) 225 / alkyl polyglycol ether combinations or a combination of APG ^(R) , alkyl polyglycol ether and modified alkyl polyglycol ether, than for the only APG ^(R) 225- containing formulations 1 -4 and A, C and D.

The formulations according to the invention require no defoamers, no thickeners for stabilization and no solubilizers. In addition, they show a rinse aid and drying effect that corresponds to the common market goods. Compared to the formulations described in European patent application 432836, the combination of APG ^(R) 225 and alkyl polyglycol ethers or modified alkyl polyglycol ethers has significantly improved the rinse aid and drying effect in plastic dishes.

Table 3 shows the scale-reducing effects of various rinse aid formulations containing citric acid. Table 3:

Recipe tableware

8 8.5

5 4.2

6 3.0

7 1.3

The use of the rinse aid containing citric acid according to the invention significantly reduces the formation of deposits. As the citric acid content increases, the anti-fouling effect of the rinse aid increases significantly. Recipe 8 contains 3% citric acid, recipe 530%, recipe 640% and recipe 750%.

Phase stability:

To determine the phase stability, 40 g of rinse aid were slowly heated to 60 ° C. If no phase separation or turbidity was observed during this process and at the temperature end point, the rinse aid formulation met the required phase stability.

Table 4:

Recipe *) Stability Solution mediator foam development

° C yes / no

APG ^(R) 225

C ₁₂ -C ₁₈ fatty alcohol * 5 EO> 60 no 2

APG ^(R) 225

C ₁₂ -C ₁₈ fatty alcohol * 7 EO> 60 no 2

APG ^(R) 225

C ₁₂ -C ₁₄ fatty alcohol * 3 EO 60 no 1

APG ^(R) 225

C ₁₂ -C ₁₄ fatty alcohol * 4 EO 60 no 1

*) Recipe: 8% by weight APG ^(R) 225 (active substance content) + 6% by weight fatty alcohol × E0 (active substance content) + 3% by weight anhydrous citric acid + 83% by weight water.

Table 4 provides information about the thermal phase stability and the foam development in the rinse aid of rinse aid formulations according to the invention.

The required application properties, namely low foaming and phase stability at ≥ 60 ° C, were then met.

Solution brokers such as B. sodium cumene sulfonate or ethanol were used

Phase stabilization not required.

Claims

1. Rinse aid for machine dishwashing based on alkyl polyglycosides of the formula C _n H _{2n + 1} -O- (C ₆ H ₁₀ O ₅ ) _x H with n = 8 - 16 and 1 <x <3, characterized in that it the alkyl polyglycosides together with optionally modified alkyl polyglycol ethers of the formula C ₈ -C ₁₈ -OR + x EO with R = H, C _m H _{2m + 1} m = 1 to 4 and x = 1 to 15, preferably 2 to 10, or mixtures this contains alkyl polyglycol ether and organic carboxylic acids.

2. Rinse aid according to claim 1, characterized in that it contains as the alkyl polyglycosides compounds of the formula C _n H _{2n + 1} -O- (C ₆ H ₁₀ O ₅ ) _x H with n = about 8-12 and 1 <x <3 .

3. rinse aid according to claim 1 and 2, characterized in that it is alkyl polyglycol ether of the formula C _p H _{2p + 1} OR + x EO with R = H, C _n H _{2n + 1} with n = 1 to 4 and p = 8-18 , x = 1 to 15, preferably 2 to 10, contains.

4. rinse aid according to claim 1 to 3, characterized in that it contains alkyl polyglycosides and alkyl polyglycol ethers in a weight ratio of about 3: 1 to 1: 1.5, preferably from about 2: 1 to about 1.5: 1.

5. Rinse aid according to claim 1 to 4, characterized in that it contains citric acid as the organic carboxylic acid.

6. rinse aid according to claim 1 to 5, characterized in that it is essentially free of solubilizers, contains no thickeners and no defoamers.

7. rinse aid according to claim 1 to 6, characterized in that it is about 0.5-20% by weight, preferably about 1-10% by weight APG ^(R) 225,

1 to 20% by weight, preferably about 3 to 10% by weight, alkyl polyglycol ether,

1-50 wt .-%, preferably about 1 - 30 wt .-% citric acid and

<1% by weight of fragrances

Balance to 100 wt .-% water.