CA1222427A - Cleaning agent based on active chlorine and alkali - Google Patents

Abstract

CLEANING AGENT BASED ON ACTIVE CHLORINE AND ALKALI

Abstract of the Disclosure A cleaning agent based on active chlorine and alkali is provided containing a minor amount of a low-foaming compound of the formula C8H17O-(C2H4O)nCH2COOM, wherein M is sodium or potassium and n is a number having an average value of 1 - 10. Preferably the weight ratio between said compound and active chlorine is 1:10 tot 1:3.

Description

CLEA~ING AGENT BASED ON ACTIVE CHLORI~E A~D ALKALI

This invention relates to a cleaning agent based on active chlorine and alkali. Such cleaning agents are used in practice for cleaning pipes and ducts and the like, for instance of apparatuses for milk processing. Usually the cleaning occurs at 40-45C and accordingly, the mi~ture should be preheated at a suitable temperature. Normally, no surfactants other than wetting agents are incorporated in such mixtures, because otherwise too much foaming would occur, particularly at the elevated temperatures and the intensive mechanical action, which accordingly would influence the cleaning action rather in a disadvantageous than in an advantageous way.
Such cleaning agents should be well discerned from the so-called thickened bleach compositions, such as disclosed in GB-A-2,076,010A and E~-A-0,072,600 which contain much more hypochlorite solution than alkali (vide page 2, line 25 of EU-A-0072600) and wherein the added surfactant serves Eor thickening the composition. The present compositions are intended for industrial use and contain alkali metal hydroxide in an amount ot at least 50% of the bleaching ayent.
Surprisingly, it has now been found that a very restricted group of ethercarboxylic acid derivatives, when added to this kind of compositions, shows a combination of a very efficient surfactant action with a low foaming, which makes it possible to incorporate these compounds in the present kind of cleaning agents, and then to use these cleaning agents at room temperature. Accordingly, an important energy saving is attained in this way which is not at the expense of the cleaning action.
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Accordingly, this invention relates to cleaning agents on the basis of active chlorine and alkali which are characterized by the fact that they also contain a minor amount of a compound of the formula 8 17 ( 2 4O)ncH2cooM~
wherein M is sodium or potassium and n is a number having an average value of 1 - 10.
The present surfactants are known per se and belong to a group of compounds which is already known for a long time for its useful properties. However, within this group of compounds the C8H17-compounds have always been considered to constitute more or less a borderline case, and compounds derived from larger hydrophobic residues were always preferred. This appears not only from the above mentioned UK-A-2,076,010 which although s-tating that -the hydrophobic residue may be a.o. a C6 20 alkyl residue,states a preference for C12-C13, and from EU-A-0,072,600 which mentions as hydrophobic group a.o. an alkyl group of 8 - 18 carbon atoms and expresses a clear pre~erence for C12-C14, but also from NL-A-7405231, wherein the hydrophobic residue again may be a C8-C20

2~,~27 aL~yl group, ~ut again is preEera31r C12-Cll alkyl, and rrom FR-A-1,09~3,~3~7 which, although Inentioning the C~}1l7 com30und as an exam~le of a possible compound, also clearly prefers hicJner all;yl compounds. It shoul~l be noted that the C~ compound is used in none oE the exam31es of the above-mentionecl publications.
In the compounds used according to the present invention the al~yl group C8El17 may be a straight chain or branched group, Eor instance n-octyl or 2-ethylhexyl. In principle one can of course also incorporate the free acid into the composition containing the active chlorinè and alkali, so that the desired salt is formed in situ. Theoretically it is of course also possible to use other salts, such as the amlnonium salt or organic ar~oniurn and amine salts, but of course in actual practice one uses preferably a salt of the etilercarboxylic acid with the same anion aa in tne alkali metal hydroxide component of the base mixture.
The other components in the system are the usual ones for this kind oE
compositions. The alkali is KOH or ~aOEi and the concentration thereof can be varied within relatively wide lirlits, generally between 20 to 250 g per liter.
A suitable concentration is in the order of 80 - 120 ~ per liter. The active chlorine in the sy.stem can be derived fron various usual compounds. Chlorine-containing bleaching lye is a cheap product, and therefore this is generally used. However, a compound like trichlorocyanuric acid or chloramine T can also be used as chlorine-producing a~Jents. Usually, the system contains about

3 - 6 ~ of active chlorine, preferably about ,~.5 h~ . As mentioned already, theamount oE alkali in such systerns is at least 50 ~ of the amourlt of bleaching agent. I-t is also posâible to replace the act:ive clllorine entirely or partially with other bleaching agents, such as peracids or peroxides.
The amount oE surfactant to be used according to the present invention can best be expressed in the weight ratio between surfactant and active chlorine. This weight ratio generally can vary from 1:10 to 1:3. Thus it is suitable to use 0.65 ~ oE the present surfactant with the above-mentioned preeerred amount of 4.5 ~ of active chlorine.
EXA~IPLES
A nur,lber of mixtures were prepared, containing 30.0 ~ hypochlorite bleaching agent (150 g chlorine/liter), 20.0 ~ of 50 % aqueous potassium hydroxide, the percentages of ethercarboxyl;c potassium salts stated herein-below, and the remainder water. The used ethercarboxylic salts had the forrnula Y 2 4 n 2 .

Example I[l III IV V VI VII VIII I~ X XL
% n = 30.51 0.75 0.5 0.5 0.25 0.~ 0.25 O n - S -- 0.75 0.5 - 0.5 0.4 - - 0.25 0.65 ~ n = 8 1 0.5 - - 0.25 - - 0.60 0.65 0.25 .. .... . _ . _ _ . .. _ _ , _ A foaming test was carried out by dissolvincJ 10 grams of eacn product in 1 liter of tap water (German hardness about 20~), shaking 50 ml of this solution vigorously by hand in a shaking cylinder oE 100 ml, and readincJ
the foam volume after 1 minute. In this experiment a foam volume oE 15 ml or less is considered satisfactory. The results of these experiments have been rendered in the following table.
Example Temperature, Cml of Foam .

III 20 ~3 VI:[ 13 6 1~ 9 For some purposes KOH is preferred in this kind of compositions and for o-ther purposes NaOH ls preferred. This does not make any difEerence for the effect of -the present invention, as will appear from the followinq two examples.
The mixtures of Examples IX and XI were prepared again, but this time with NaOH. rrhese compositions are named Examples IXa and XIa. They were also subjected to the above foaming test, and this at 12C and 20C. The results have been rendered hereinbelow, and for the sake oE clarity the corresponding results with KOH from the above table have been reiterated here.

Example1 oE Foam a-t 12Cml oE Foam at 20C

IXa 10 7 XIa 11 6

Claims (3)

The embodiments of the invention in which an exclusive property of privilege is claimed, are defined as follows:

1. A cleaning agent based on active chlorine providing bleaching agent and alkali metal hydroxide in an amount of at least 50 % of the bleaching agent, characterized by containing a minor amount of a low-foaming compound of the formula C8H17O-(C2H4O)nCH2COOM, wherein M is sodium or potassium and n is a number having an average value of 1 - 10.

2. A cleaning agent according to claim 1, characterized by the fact that the weight ratio between said low-foaming compound and active chlorine is 1:10 to 1:3.

3. A cleaning agent according to claim 1 or 2, characterized by the fact that it contains 3 - 6 % of active chlorine in the form of bleaching lye.