Thixotropic liquid sanitary cleanser and its uses

The invention relates to a liquid cleanser with thixotrope properties and its use as a liquid sanitary cleaning agent, in particular for cleaning toilets, washbowls, shower cabinets, shower tubs and swimming pools as well as kitchen sinks. The liquid cleanser contains along with usual cleanser additives in aqueous solution as a surface-active agent one or more compounds selected from the group of alkylamidobetaines, alkylaminobetaines, alkylbetaines, alkyl polyglycol ether carboxylic acids and/or fatty alcohol ethoxylates in mixture with pyrogenic silicic acid and at least one organic acid selected from the group of citric acid, lactic acid, tartaric acid, maleic acid, malic acid, glutaric acid, adipic acid, acetic acid and formic acid.

This invention relates to a liquid cleanser with thixotrope properties 
which contains a surface-active agent and an organic acid along with usual 
cleanser additives in aqueous solution, and to its use as a liquid 
sanitary cleaning agent, in particular for cleaning toilets, washbowls, 
shower cabinets, shower tubs and swimming pools as well as kitchen sinks. 
Conventional acidic liquid toilet cleaning agents contain along with 
surface-active agents substantially organic acids (e.g. formic acid, 
acetic acid or citric acid) or inorganic acids (e.g. phosphoric acid or 
hydrochloric acid) and polysaccharides as thickening agents as well as 
usual further additives such as stabilizers, dyes and scents. 
Known acidic liquid toilet cleaning agents are effective for example in 
removing lime and urine deposits as well as in destroying bacteria and bad 
smells which form predominantly on the lime and urine deposits. 
The most frequently used relatively strong acids, such as hydrochloric 
acid, phosphoric acid and formic acid, belong to water danger class 1. 
Phosphoric acid furthermore has a eutrophic effect. Hydrochloric acid and 
formic acid are considered strong irritants for the eyes, respiratory 
tract and mucous membranes so that liquid toilet cleansers containing 
these acids can already be recognized by their keen and sharp smell. The 
stated strong acids are furthermore very difficult to perfume. Inorganic 
acids and formic acid therefore involve a potential danger because of 
their corrosive effect and should not be used for household cleaning 
agents if possible. 
The thickening agents contained in known toilet cleaning agents are 
intended to increase the viscosity of the cleaning agent and ensure that 
the acidic cleaning solution can act as long as possible on the vertical 
surfaces of a toilet bowl. 
However, the viscosity of a toilet cleanser cannot be increased at will, 
the lime solvent power decreasing with increasing viscosity as a result of 
diffusion problems of its lime-dissolving components on the toilet surface 
to be treated, and problems furthermore occurring with respect to the 
distribution of the cleanser, which becomes more difficult with increasing 
viscosity. This limits the exposure time and the exposure concentration of 
the lime-dissolving components of the toilet cleansers and thus their 
cleaning power, in particular their lime solvent power (LSP). 
The problem of the invention was therefore to develop an improved liquid 
cleanser which has a higher cleaning power, in particular improved lime 
solvent power, while using weaker, less polluting acids without the 
abovementioned problems occurring. 
It was found that this problem can be solved by considerably improving the 
adhesion of a sufficiently thick cleaning film to the surface to be 
cleaned by using pyrogenic silicic acid, which in combination with certain 
organic acids and surface-active agents gives the liquid cleaning agent 
thixotrope properties. 
It was surprisingly found in particular that thixotropic acidic aqueous 
cleaning solutions (containing organic carboxylic acids) with clearly 
higher lime solvent power can be obtained with various surface-active 
agents, based on the same active content, and pyrogenic silicic acid. 
The subject-matter of the invention is a liquid cleanser with thixotrope 
properties which contains a surface-active agent and an organic acid along 
with usual cleanser additives in aqueous solution, characterized in that 
it contains as a surface-active agent one or more compounds selected from 
the group of alkylamidobetaines, alkylaminobetaines, alkylbetaines, alkyl 
polyglycol ether carboxylic acids and/or fatty alcohol ethoxylates in 
mixture with pyrogenic silicic acid and at least one organic acid selected 
from the group of citric acid, lactic acid, tartaric acid, maleic acid, 
malic acid, glutaric acid, adipic acid, acetic acid and formic acid.

The surface-active agents to be used according to the invention are ones 
whose alkyl group or fatty acid group is a saturated or unsaturated alkyl 
group with 10 to 18, preferable 12 to 14, carbon atoms, and the alkyl 
polyglycol ether carboxylic acids and/or fatty alcohol ethoxylates used as 
surface-active agents preferably contain 2 to 15, in particular 3 to 7, 
specifically 3, ethylene oxide units per molecule. 
An especially advantageous surface-active agent is alkylamidopropyl 
betaine, which is preferably used in 30% form. 
Of the abovementioned organic acids, citric acid is especially 
advantageous. 
The pyrogenic silicic acid preferably used according to the invention is 
Aerosil, in particular a type 200 one, and/or Cab-o-Sil, in particular a 
type M5 one. 
The inventive liquid cleanser can additionally contain glycol and 
optionally one or more preservatives, in particular benzoic acid, 
optionally one or more usual perfume oils and/or optionally one or more 
usual dyes. 
The inventive cleanser preferably contains the pyrogenic silicic acid in a 
quantity of 1.0 to 5.0%, specifically 1.8 to 2.5%, based on the total 
weight of the cleanser. 
The organic acid is preferably contained in the inventive cleanser in a 
quantity of 1 to 40%, in particular 5 to 15%, based on the total weight of 
the cleanser. 
The inventive cleanser preferably contains the abovementioned 
surface-active agent in a quantity of 0.5 to 5.0%, in particular 1.8 to 
2.5%, based on the total weight of the cleanser. 
The glycol, which can be contained in the inventive cleanser as an optional 
component, preferably exists in a quantity of 1 to 10%, in particular 1.5 
to 5%, based on the total weight of the cleanser. 
If the inventive cleanser contains a preservative and optionally a perfume 
oil and optionally a dye, these components are preferably present in a 
quantity of 0.2 to 1.0% (preservative) and a total quantity of 0 to 2%, in 
particular up to 0.5% (perfume and dye), based on the total weight of the 
cleanser in each case. 
If the inventive cleanser contains a fatty alcohol ethoxylate as a 
surface-active agent, this is preferably one with an ethylene oxide 
content of 2 to 12 mol, preferably 3 mol, which is present in a quantity 
of preferably 0.1 to 2%, in particular 0.5 to 1%, based on the total 
weight of the cleanser. 
An especially preferred inventive cleanser has the following composition, 
based on the total weight of the cleanser: 
about 2.2% pyrogenic silicic acid 
about 2.0% glycol 
about 0.3% preservative (preferably benzoic acid) 
about 7.0% citric acid 
about 2.0% alkylamidopropyl betaine (30%) 
about 0.5% perfume oil and dye 
balance water. 
According to a further aspect the present invention relates to the use of 
the above-described cleanser as a liquid sanitary cleaning agent, in 
particular for cleaning toilets, washbowls, shower cabinets, shower tubs 
and swimming pools as well as sinks in kitchens and labs. 
With the inventive liquid cleaning agent one can increase the lime solvent 
power (LSP) by approx. 20% to 50% over toilet cleansers on the market, as 
indicated by the following survey of LSP values which were determined by 
the method of quality recommendation for acidic toilet cleansers (of the 
Industrieverband Putz- and Pflegemittel e.V. in the version of 1993) and 
classified as follows: 
LSP&gt;1.3=very good 
LSP 0-7-1.3=satisfactory 
LSP&lt;0.7=inadequate 
Comparison of LSP values of inventive cleansers and prior art cleansers 
a) Inventive cleansers 
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Inventive cleanser with 
LSP value 1.44 
abovementioned composition 
(very good) 
Inventive cleanser with 
LSP value 1.71 
same composition as above but 
(very good) 
with alkylbetaine instead 
of alkylamidopropyl betaine 
Inventive cleanser with 
LSP value 1.91 
same composition as above but 
(very good) 
with alkyl polyglycol ether 
carboxylic acid instead of 
alkylamidopropyl betaine 
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b) Comparable values for commercial products (liquid toilet cleansers based 
on organic carboxylic acid with the exception of formic acid): 
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WC-frisch LSP value 1.13 (satisfactory) 
00 Plus Formel LSP value 1.05 (satisfactory) 
Frosch Essigreiniger 
LSP value 1.21 (satisfactory) 
Tarax LSP value 1.11 (satisfactory) 
WC Ente, green LSP value 1.22 (satisfactory) 
Clinar LSP value 0.98 (satisfactory) 
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The inventive liquid cleanser thus has clearly improved LSP values over the 
prior art, which were unforeseeable for the expert in the field. This is 
presumably due to the fact that the liquid no longer runs away from the 
vertical surfaces during cleaning so that the exposure time and exposure 
concentration of the lime solvents is clearly increased while the 
diffusion of lime solvent on the surface to be treated is simultaneously 
improved. 
Conversely, if limited demands are made on lime solvent power the 
concentration of lime-dissolving agent can be clearly reduced and the 
environmental acceptability of the inventive liquid cleanser thereby 
improved further, or stronger lime-dissolving acids can be used in lower 
concentration with environmental acceptability still being sufficient. 
The inventive liquid cleanser with thixotrope properties can expediently be 
applied uniformly to the surface to be cleaned from a spray container with 
a spherical spray head having preferably four holes disposed each 
perpendicular thereon. The inventive liquid cleanser becomes temporarily 
thinner by being sprayed and assumes a thicker consistency again when 
hitting the surface to be cleaned, so that the inventive liquid cleanser 
can be applied to the surface to be cleaned in a better-sticking, thicker 
layer without the abovementioned problems with respect to distribution and 
diffusion properties occurring.