EP0570619A1 - Process for cleaning bathroom fittings - Google Patents

Abstract

Process for cleaning bathroom fittings and other solid surfaces with cleaning foam, characterised in that the foam is generated from an aqueous liquid which contains as essential surfactant an alkyl polyglycoside of the formula I R-O(-G)n (I> in which R is a long-chain alkyl radical with 8 to 22 C atoms, G is a glycosidically linked radical of a monosaccharide and n is a value between 1 and 10.

Description

The present invention relates to a method for cleaning solid surfaces, in particular fittings in bathrooms and similar rooms.

Instead of the previously usual cleaning with aqueous liquids that were applied to the surfaces with rags or sponges, foam cleaners are increasingly being used today. The use of the cleaning agent in the form of a foam has the advantage that, due to the better adhesion of the foam to the surfaces, even vertical and inclined surfaces can be evenly provided with cleaning agent without the cleaning agent running off these surfaces immediately. The foam is generally generated immediately when the cleaning liquid is sprayed onto the surfaces with the aid of suitable devices: in the case of hand-operated foam spray pumps, the liquid emerging from the spray nozzle is mixed with air in such a way that it hits the surface as foam; in aerosol products, the propellant gas is used to generate the foam. Although many foam preparations have been proposed for this cleaning process, there are still a number of problems with this process that are still unsolved. For example, many preparations require thorough rinsing with water and dry wiping in order to prevent residues of the cleaning agents from remaining visible on high-gloss surfaces, for example mirrors, tiled surfaces or chrome surfaces. The causes are the lack of uniformity and the lack of transparency of the detergent residues. Another problem in modern bathrooms is the cleaning of numerous plastic objects, such as bathtubs, shower cubicles or fittings. The various plastics encountered here, such as polymethacrylate, polypropylene, polyacetal and impact-resistant polystyrene (ABS), are subject to very different degrees of stress corrosion cracking, which is considerably reinforced by surfactant cleaning agents becomes. Another problem arises from the necessity to use flammable propellants, such as propane / butane, in aerosol preparations instead of the fluorochlorohydrocarbons which were customary in the past. The foam produced with it is more or less flammable under unfavorable conditions and then represents a potential hazard.

The object of the present invention was therefore to develop an overall more suitable cleaning method which in particular does not have the disadvantages mentioned above.

The invention relates to a method for cleaning bathroom fittings and other solid surfaces with cleaning foam, in which the foam is generated from an aqueous liquid which contains an alkyl polyglycoside as an essential surfactant. The aqueous solution preferably additionally contains small amounts of monohydric alcohols having 2 to 3 carbon atoms, in particular ethanol.

The new cleaning process is characterized by a good cleaning effect even on vertical surfaces and leaves even, if not rinsed or polished, even and completely transparent residues that are practically invisible even on high-gloss surfaces. Despite the high cleaning power of the surfactant solution used, no acceleration of stress corrosion cracking is observed on the plastic materials commonly used in bathrooms. The aqueous surfactant solution used foams easily and provides very stable foams which are practically non-flammable even when propane / butane is used as an aerosol propellant.

The alkyl polyglycosides used as surfactants in the aqueous liquid are compounds of the general formula I:



RO (-G) _n I



in which R is a long-chain alkyl radical having 8 to 22 carbon atoms, G is a glycosidically bonded radical of a monosaccharide and n is a value between 1 and 10.

Alkyl polyglycosides have been known as surface-active substances for more than 50 years and can be produced in various ways. In this context, reference should only be made to European patent application 362 671, which also cites literature on older processes.

A synthesis which is important on an industrial scale today consists essentially in the acid-catalyzed condensation of monosaccharides of the aldose type (HO-G) with long-chain alcohols (R-OH) which contain 8 to 22, preferably 8 to 18, C atoms. Alkyl glycosides of the formula I are formed when water escapes



RO (-G) _n



the value of n can be varied within wide limits by the choice of the reaction conditions. Alkyl glycosides of the formula I with n = 1 to 10 can be used according to the invention; Compounds with values for n between 1 and 6, in particular 1 to 2, are preferred. In products in which n is greater than 1, n naturally represents a statistical mean.

In the preparation of the alkyl glycosides, it is also possible to start from oligosaccharides or polysaccharides, which are then depolymerized to lower fragments in the course of the acid-catalyzed reaction by hydrolysis and / or alcoholysis before the alkyl glycosides of the formula I form. Mixtures of different reducing monosaccharides or polysaccharides which contain different monosaccharide units can also be used as starting materials, and if n is greater than 1, correspondingly mixed alkyl glycoside molecules can be formed.

The following monosaccharides are preferably suitable as starting materials: glucose, mannose, galactose, arabinose, apiose, lyxose, gallose, altrose, idose, ribose, xylose and talose as well as the oligo- and polysaccharides composed of these monosaccharides, for example maltose, lactose, maltotriose, hemicellulose , Starch, partial hydrolyzates of starch and sugar syrup. In the context of the invention, however, alkyl glycosides are preferred which are composed of the same monosaccharide units. Alkyl glycosides in which the rest (-G) from which glucose is derived. For these compounds, which are also referred to as alkyl glucosides, glucose, maltose, starch and other oligomers of glucose are used accordingly as starting materials.

In the preparation described above, the alkyl part R is derived from long-chain, optionally unsaturated, preferably primary alcohols which can be branched, but are preferably not branched. Examples are the synthetic oxo alcohols with 9 to 15 C atoms and the fatty alcohols obtained from natural fatty acids with 8 - 22 C atoms. The fatty alcohols with 8 to 18 carbon atoms and the oxo alcohols with 11 to 15 carbon atoms are preferred, but in particular the fatty alcohols with 8 to 10 carbon atoms or with 12 to 14 carbon atoms.

In addition to the actual alkyl glycosides of formula I, industrially manufactured products generally also contain certain proportions of free alcohol R-OH and non-acetalized saccharides, optionally in oligomerized form. In most cases, these technical impurities do not interfere with the intended use. If alcohol mixtures are used in the production of the alkyl glycosides, for example alcohols based on natural fats, the alkyl glycosides are of course also mixtures with a correspondingly larger meaning of R in formula I.

In addition to the alkyl polyglycosides, the cleaning liquids used in the process according to the invention can contain further surfactants, provided that the advantageous effects of the process are not impaired thereby. These are, in particular, anionic surfactants, of which long-chain alkyl sulfates should be mentioned in particular. They are preferably used as sodium salts. Fatty alcohol sulfates with about 12 carbon atoms in the alkyl chain are particularly preferred. The total content of surfactants in the aqueous liquid used according to the invention is preferably between approximately 1% and approximately 6% by weight, in particular between approximately 2 and approximately 4% by weight.

As organic solvents, the aqueous liquids used according to the invention can contain monohydric alcohols having 2 to 3 carbon atoms, ie ethanol, n-propanol and isopropanol, of which in turn ethanol is particularly preferred. The alcohol content in the aqueous liquid is preferably between 0.5 and 12% by weight and is in particular between about 1 and 5% by weight. The addition of the alcohols improves the cleaning result on certain soils in the process according to the invention without promoting stress corrosion corrosion on plastic surfaces and without increasing the flammability of the foams. An overall particularly favorable result is obtained when the weight ratio of surfactant to alcohol in the solution is between about 1: 1.5 and about 2: 1.

In addition to the constituents mentioned, the aqueous liquids used according to the invention can contain small amounts of other active ingredients and additives, as are customary in sanitary cleaners of this type. If such auxiliary substances and additives are also used, it is of course a prerequisite that these substances do not impair the positive results obtained with the process according to the invention. Examples of such active ingredients are lime-dissolving organic acids, such as citric acid, acetic acid or lactic acid or their water-soluble salts, which are preferably present in amounts of 2 to 6% by weight, based on the total aqueous liquid. The pH of the aqueous liquid can be adjusted from weakly acidic to weakly alkaline and is preferably between about 4 and about 9. Examples of other auxiliaries and additives are dyes, corrosion inhibitors, antimicrobial agents or preservatives and perfume. The aqueous liquids used according to the invention preferably contain no polyhydric alcohols and no nonionic surfactants of the alcohol ethoxylate type.

In the method according to the invention, foam is preferably generated directly when the liquid emerges from the sprayers. In the case of hand spray pumps, this is achieved by a special design of the spray head, which ensures that the aqueous liquid emerging from the spray nozzle is mixed with air to such an extent that the liquid already hits the surface as a foam. Appropriately designed spray pumps are commercially available. When used as an aerosol, suitable design of the spray mechanism, taking into account the composition of the cleaning liquid, must ensure that together with sufficient quantities of propellant gas always escape from the liquid, which then lead to foaming of the liquid. If necessary, shake before use. The appropriate design of the aerosol container, intake manifold and valve is part of the routine work of a person skilled in the art and is therefore not to be explained in more detail here. The amount of liquid sprayed onto the surface to be cleaned in the course of the cleaning process is usually between about 10 g and about 60 g / m 2; in particular 20 g to 40 g / m². The foam is expediently distributed as evenly as possible over the surface to be cleaned and can then develop its cleaning action automatically. However, the surfaces are preferably subsequently wiped with a damp cloth or a sponge, with larger surfaces being rinsed out with clear water from time to time. The treated surfaces can of course also be rinsed with water, but this is generally not necessary as the remaining cleaning agent residues dry completely transparent and remain practically invisible.

Examples

• A) Rückstandstransparenz
  Als Testfläche dienten kleine senkrecht gestellte Spiegel mit den Abmessungen 70 x 200 mm. Pro Spiegel wurden jeweils 4 g der zu untersuchenden Reinigungsflüssigkeit in Form von Schaum gleichmäßig aufgesprüht. Nach dem Ablaufen des Schaums und einer Trockenzeit von 30 Minuten wurden verbliebenen Rückstände visuell beurteilt und nach folgender Skala benotet:
  1 = vollkommen transparent,
  2 = transparent mit leichten Schlieren,
  3 = matter Rückstand.
• B) Schädigung von Kunststoffen
  Diese Prüfungen wurden an verschiedenen Kunststoffen in Anlehnung an die deutsche Norm DIN 53 449 durchgeführt, wobei sowohl das Stifteindrückverfahren (DIN Teil 1) als auch das Biegestreifenverfahren (DIN Teil 3) angewandt wurden.
• B1) Stifteindrückverfahren
  In einen entsprechend den Normvorschriften dimensionierten Kunststoffprobestab wurde ein Stahlrundstift in eine vorhandene Bohrung eingedrückt und dadurch eine Vorspannung erzielt. Die Probestücke wurden 10 Minuten in die Reinigungsmittelflüssigkeit eingetaucht, dann entnommen und trocknen gelassen. Die Beurteilung von aufgetretenen Rissen erfolgte mit Hilfe eines Mikroskopes nach 24 Stunden und führte zu folgender Benotung:
  1 = unverändert
  2 = Rißansatz, kleiner Riß
  3 = Riß durchgehend
  4 = Bruch
• B2) Biegestreifenverfahren
  Der Norm entsprechend dimensionierte Kunststoffstreifen wurden mit Diisopropylether gereinigt, in einer Spannvorrichtung vorschriftsmäßig befestigt und am Streifenende mit 0,8 kg belastet, um eine Vorspannung zu erzielen. Auf den gespannten Kunststoff wurden dann Filterpapierstreifen (15 x 200 mm) aufgelegt und mit 1 ml der Reinigungsflüssigkeit getränkt, ohne die Schnittflächen der Kunststoffstreifen zu benetzen. Die Einwirkzeit betrug 15 Minuten, wobei Verdunstungsverluste mit zusätzlicher Flüssigkeit ausgeglichen wurden. Nach dieser Zeit wurden die Filterpapierstreifen entfernt, anhaftende Produktreste aber nicht beseitigt. Die Beurteilung erfolgte nach insgesamt 24 Stunden mit folgender Benotung:
  1 = unverändert
  2 = Silberschimmmer
  3 = Rißbildung
  4 = Bruch
  In den Prüfungen B1 und B2 wurden jeweils 5 Kunststoffstreifen in gleicher Weise geprüft.
• C) Entflammbarkeit von Aerosol-Schäumen
  Die zu prüfenden Reinigungsflüssigkeiten wurden aus einer Aerosoldose unter standardisierten Bedingungen mit einem Gemisch aus Butan/Propan (Gewichtsverhältnis 75 : 25) versprüht, wobei vor dem Sprühen durch 20maliges Schütteln eine gleichmäßige Verteilung des Treibgases in der Flüssigkeit erreicht wurde. Zum Test wurden auf ein Uhrglas von 12 cm Druchmesser innerhalb von 4 bis 5 Sekunden 20 g Schaum aufgesprüht. Nach einer Wartezeit von 10 Sekunden wurde durch Annäherung eines brennenden Streichholzes die Entflammbarkeit der Schaumoberfläche geprüft. Die Beurteilung richtete sich nach der Länge der auftretenden Flammenerscheinung, wobei die Benotung zwischen 1 = nicht entflammbar (keine Flammerscheinung) bis 5 = stark entflammbar (Wirkstoff brennt weiter) vorgenommen wurde.
• D) Schaumstabilität
  Das zu prüfende Aerosolprodukt wurde durch 20maliges Schütteln intensiv vermischt. Danach wurden 30 g Schaum in ein weites 1000 ml-Becherglas eingesprüht. Nach 10 Minuten Standzeit wurde das Schaumvolumen (SV) an der Graduierung abgelesen und das gebildete Flüssigkeitsvolumen (FV) durch Ausgießen in einen Meßzylinder ermittelt.
  Die Berechnung der Schaumstabilität wurde wie folgt durchgeführt (SV, WV in ml):
  
  Benotung:
  > 20 = Note 1: stabil
  10-20 = Note 2: mäßig stabil
  < 10 = Note 3: instabil
  Note 4: kein Schaum

Die nachfolgenden Tabellen 1 und 2 geben die Zusammensetzung der verwendeten Reinigungsflüssigkeiten an, die im Reinigungsverfahren als Aerosolschaum bzw. als Schaum aus Handsprühpumpen angewandt wurden. Die Füllung der Aerosoldosen bestand aus 448 g der Reinigungsflüssigkeit und 28,6 g eines Gemisches aus Butan/Propan (75 : 25) und wurde vor jedem Sprühvorgang durch Schütteln vermischt.

A number of cleaning fluids, the exact compositions of which are given in the following tables, were tested in several tests for their usability in the foam cleaning process on bathroom fittings and similar surfaces. The following test methods were used:

• A) Residue transparency
  Small vertically placed mirrors measuring 70 x 200 mm served as the test area. 4 g of the cleaning liquid to be examined in the form of foam were sprayed uniformly onto each mirror. After the foam had run out and had dried for 30 minutes, the remaining residues were assessed visually and graded on the following scale:
  1 = completely transparent,
  2 = transparent with slight streaks,
  3 = matt residue.
• B) Damage to plastics
  These tests were carried out on various plastics based on the German standard DIN 53 449, whereby both the pin insertion method (DIN part 1) and the bending strip method (DIN part 3) were used.
• B1) Pen insertion process
  A round steel pin was pressed into an existing hole in a plastic test specimen dimensioned according to the standard regulations, thereby achieving a preload. The test pieces were immersed in the detergent liquid for 10 minutes, then removed and allowed to dry. Cracks that occurred were assessed with the aid of a microscope after 24 hours and resulted in the following grading:
  1 = unchanged
  2 = crack set, small crack
  3 = continuous crack
  4 = break
• B2) Bending strip procedure
  Plastic strips dimensioned according to the standard were cleaned with diisopropyl ether, fastened in a tensioning device in accordance with regulations and loaded with 0.8 kg at the end of the strip in order to achieve a pretension. Filter paper strips (15 x 200 mm) were then placed on the stretched plastic and soaked with 1 ml of the cleaning liquid without wetting the cut surfaces of the plastic strips. The exposure time was 15 minutes, whereby evaporation losses were compensated with additional liquid. After this time, the filter paper strips were removed, but adhering product residues were not removed. The assessment was made after a total of 24 hours with the following rating:
  1 = unchanged
  2 = silver shimmer
  3 = cracking
  4 = break
  In tests B1 and B2, 5 plastic strips were tested in the same way.
• C) Flammability of aerosol foams
  The cleaning liquids to be tested were sprayed from an aerosol can under standardized conditions with a mixture of butane / propane (weight ratio 75:25), with a uniform distribution of the propellant gas in the liquid being achieved by shaking 20 times. For the test, 20 g of foam were sprayed onto a 12 cm diameter watch glass within 4 to 5 seconds. After a waiting time of 10 seconds, the flammability of the foam surface was checked by approaching a burning match. The assessment was based on the length of the appearing flame, the rating being between 1 = non-flammable (no flame) to 5 = highly flammable (active substance continues to burn).
• D) Foam stability
  The aerosol product to be tested was mixed intensively by shaking 20 times. Then 30 g of foam were sprayed into a wide 1000 ml beaker. After standing for 10 minutes, the foam volume (SV) was read from the graduation and the liquid volume (FV) formed was determined by pouring it into a measuring cylinder.
  The foam stability was calculated as follows (SV, WV in ml):
  
  Grading:
  > 20 = grade 1: stable
  10-20 = grade 2: moderately stable
  <10 = grade 3: unstable
  Grade 4: no foam

Tables 1 and 2 below give the composition of the cleaning liquids used, which were used in the cleaning process as aerosol foam or as foam from hand-spray pumps. The filling of the aerosol cans consisted of 448 g of the cleaning liquid and 28.6 g of a mixture of butane / propane (75:25) and was mixed by shaking before each spraying process.

Testing the cleaning agent solutions from Tables 1 and 2 gave the following results: Test procedure and evaluation example A B1 B2 C. D 1 1 1 1 2nd 1 2nd 1 1 1 1 1 3rd 1 1 1 1 1 4th 1 1 1 1 1 5 1 1 1 3rd 3rd 6 1 1 1 5 3rd 7 3rd 2nd 2nd 1 4th 8th 3rd 3rd 2nd 2nd 2nd 9 3rd 2nd 4th 2nd 1 10th 3rd 3rd 3rd 5 3rd 11 1 1 1 - - 12th 1 1 1 - - 13 1 1 1 _ - 14 1 1 1 - - 15 1 1 1 - - 16 3rd 3rd 4th - - 17th 3rd 3rd 4th - -

It is clear from the results that an overall better result can be achieved with the cleaning method according to the invention than when using other (5-8) and commercially available foam cleaning agents (9, 10, 16, 17).

Claims (9)

Process for cleaning bathroom fittings and other solid surfaces with cleaning foam, characterized in that the foam is produced from an aqueous liquid which contains an alkyl polyglycoside as the essential surfactant. The method of claim 1, wherein the aqueous liquid contains an alkyl sulfate as a further surfactant in addition to alkyl polyglycoside. Method according to one of Claims 1 or 2, in which the surfactant content in the aqueous liquid is between 1 and 6% by weight, preferably between 2 and 4% by weight. Method according to one of claims 1 or 2, in which the aqueous liquid used to produce the foam contains a monohydric alcohol having 2 or 3 carbon atoms, preferably ethanol. A method according to claim 4, wherein the alcohol content in the aqueous liquid is 0.5 to 12% by weight, preferably 1 to 5% by weight. The method of claim 4, wherein the weight ratio of surfactant to alcohol in the aqueous liquid is 1: 1.5 to 2: 1. Method according to one of claims 1 or 2, in which the cleaning liquid as a further active ingredient is a water-soluble organic carboxylic acid, preferably from the group citric acid, acetic acid and lactic acid and mixtures thereof, or salts of these acids, in particular in amounts between 2 and 6% by weight. , contains. Method according to one of claims 1 or 2, wherein the aqueous liquid has a pH between 4 and 9. A method according to claim 1, in which between 1 and 60 g of cleaning liquid in the form of foam are sprayed on per 1 m² of surface to be cleaned and the surface is then wiped with a damp cloth or sponge.